Recent Spike in Acute Flaccid Myelitis Cases
As of September 2016, there have been 89 cases of Acute Flaccid Myelitis (AFM) across 33 states in the United States (1). There has been a recent spike of...
On August 1, 2016 in Northern Russia, a 12-year-old boy died of anthrax, marking the first fatal case among 20 confirmed infected humans from the Yamalo-Nenets region in Siberia. The anthrax outbreak...
On December 14th, the Centers for Disease Control and Prevention (CDC) designated Brownsville, Texas as a Zika cautionary zone after the Governor Greg Abbott reported confirmed cases of local transmission [1, 2]. Texas’ first locally transmitted case of Zika was announced on November 28 and five more cases have been identified since. Five of the cases live very close to the index case and developed Zika-like symptoms several days before mosquito control efforts went underway . On December 22, the Department of State Health Services (DSHS) announced that a sixth case was identified and does not appear to be connected with the other cases . This is the second state in the US to have reported local transmission of Zika virus, a mosquito-borne and sexually transmitted virus, widely feared because of the devastating teratogenic effects it can cause, including – but not limited to – microcephaly.
Brownsville, Texas is the county seat of Cameron County and is situated on the southeastern tip of the Texas-Mexico border. South of Brownsville, across the Rio Grande River, is the Mexican city of Matamoros. Travel across the border is common between the two cities. The Mexican Tourism Board has been reporting mosquito transmission of Zika on their side of the border at least since April 15, 2016, and it is possible that the virus has been circulating in Matamoros . Approximately six months earlier, the DSHSof Texas announced the first local transmission of chikungunya in Cameron County and have also reported local transmission of dengue in previous years [6, 7]. It may only be a matter of time before Zika joined these other arborviruses in spreading to Texas.
Zika Symptoms and Birth Defects
The symptoms of Zika virus infection are generally mild and commonly include a fever, rash, joint pain, and/or conjunctivitis. However, it should be noted that most people exhibit no symptoms at all [8, 9]. Asymptomatic cases are a cause of concern because these individuals may unknowingly spread the disease to their sexual partners or to uninfected mosquitoes, which may end up transmitting the virus to other humans. Infected pregnant women are largely at risk as the virus has been associated with microcephaly in infants infected in utero, but it is not fully understood when pregnant women are at the greatest risk. Two new studies further illuminate the dangers of the Zika virus in child-bearing women. Both studies reported that infection during the first trimester had the greatest chance of yielding adverse outcomes for the fetus [9, 10]. One study of symptomatic and asymptomatic women registered with the US Zika Pregnancy Registry showed that 6% of the babies born from the study population had birth defects, with the majority of them being microcephaly (18 births out of 26 total births with defects) . Other abnormalities were also seen in infected infants, both with and without microcephaly. These widely differing teratogenic effects included neural tube defects, congenital contractures, deafness, intraocular calcifications, and many other brain or eye abnormalities . A second study in Brazil of symptomatic pregnant women only demonstrated unsettling results in that 46% of the children born from these women had birth defects but only four of the these 58 children had microcephaly . Some of these Brazilian women were co-infected with other diseases, such as chikungunya or syphilis, and many of them had previous dengue infections . The large discrepancy of the amount of birth defects may be due to an unknown condition that exists between the two study populations. Differences in the populations include previous dengue infections, geography, and the possible inclusion of false positive women in one of the studies . Regardless of the real risk of Zika related birth defects, it is highly recommended that pregnant women protect themselves in areas where Zika may be circulating.
Babies born without any apparent birth defects to Zika infected mothers may have or develop problems as they grow. The CDC and researchers from Brazil have reported 13 cases where children with normal head sizes had laboratory evidence of congenital Zika infection . Of these children, 11 showed decreased head growth at as early as five months of age and were later diagnosed with microcephaly . All of the 13 children born with normal head sizes were found to have adverse brain abnormalities, such as subcortical calcifications and motor disabilities . These findings solidify the importance of early neuroimaging and follow-up exams for children exposed to the Zika virus .
For mothers faced with raising a child with Zika-related birth defects, one can only guess at the life-long cost of treatment and care. The director of the CDC, Dr. Tom Frieden, estimated in a press conference in April that a single child with birth defects can cost over $10 million USD . Barbara Altman, a woman who has a 53 year old microcephalic son, estimates Medicaid payments for the care of her child costs $395,600 a year and over $21 million dollars over his lifetime so far . As of November 30th, there have been at least 32 children born with Zika-related birth defects in the US alone , which may cost families and taxpayers over $12.5 million dollars a year using Ms. Altman’s estimate.
The principle vector of the Zika virus, the Aedes aegypti mosquito, is estimated to be present in roughly half of the contiguous United States . It is imperative to keep these local mosquitoes from becoming infected with the virus as this will prevent local transmission. Many varied public health interventions to control mosquito populations have been used for decades, but evaluating their effectiveness has proven inconclusive . A meta-review published on December 7th compared studies that reviewed biological, chemical, educational, and integrated (any combination of the previous three) vector control strategies for Aedes mosquitoes . The study showed that biological control and educational programs reduced mosquito populations and breeding habitats respectively, but integrated control strategies had mixed results . Chemical control may not be able to sustainably reduce mosquito populations over time and may be associated with a false sense of security that leads to decreased community involvement .
Due to the uncertain effectiveness of mosquito control strategies, it cannot be stressed enough that the population should take steps to reduce the risk of contracting the Zika virus and make changes to their homes and backyards to prevent Aedes mosquitoes from reproducing. Aedes mosquitoes are aggressive biters that are highly adapted to peridomestic environments and prefer human hosts [17, 18]. Once a week, any items that may contain standing water, such as tires or flowerpots, should be turned over to remove the water where mosquitoes may lay their eggs . Indoor and outdoor insecticides can be used to treat areas where mosquitoes may rest while insect repellants can be used when people go outside in areas where Zika is circulating [3, 19].
Since January 2015, at least 4,757 Americans have been infected, and at least 216 of these cases getting the virus from local mosquitoes . All but six of these local transmissions were in Florida, where efforts to break the transmission cycle have been ongoing since the first local cases were discovered in July . An infected person importing the virus is the most common way Zika circulates into new areas . Travelers coming back from areas where Zika is present should take precautions against local mosquitoes for at least three weeks . Safe sex practices should also be adhered to for at least six months for men and at least eight weeks for women after travelling or developing symptoms to prevent human-to-human transmission . If the local mosquito population has circulating Zika virus, widespread insecticide spraying should be undertaken to reduce the mosquito population. However, success relies on the combined efforts of the population and health authorities to prevent the spread of this disease.
Local transmission in Texas represents a new front in the fight to prevent Zika from establishing itself in the United States. Vector control efforts alone may not be enough to prevent Zika infected mosquitoes from establishing themselves into new areas. Preventing the spread of Zika must be achieved through a combined effort of health authorities and the population to keep this disastrous disease from further harming unborn children.
17. Bouzid, M., et al., Public Health Interventions for Aedes Control in the Time of Zikavirus– A Meta-Review on Effectiveness of Vector Control Strategies. PLOS Neglected Tropical Diseases, 2016. 10(12): p. e0005176.
18. CDC. Transmission & Risks. 2016 October 24, 2016 December 16, 2016].
A mumps outbreak in Arkansas continues to grow at an alarming rate. As of December 8th, the total number of suspected and confirmed cases of mumps in Arkansas now stands at 1,898. In Arkansas alone, the number of cases reported exceeds that of the national total for 2015. Of great concern in this outbreak, 90% to 95% of school-aged children and 30% to 40% of adults involved in the outbreak have been fully immunized . As of December 6, eleven counties are involved, they are: Benton, Carroll, Clark, Conway, Faulkner, Garland, Howard, Madison, Pulaski, Washington and Yell .
What is Mumps?
Mumps is an infectious viral disease that is transmitted through saliva or mucus, from the mouth, nose, or throat. Common symptoms include fever, headache, muscle aches, and tiredness. The infection is characterized by the puffy cheeks and swollen jaw that it causes. Symptoms typically appear 16-18 days after infection, and most people recover completely within several weeks. Outbreaks are more common in crowded environments, such as college campuses, and with behaviors that result in sharing saliva occur, such as in a preschool where toys are shared .
The MMR (measles, mumps, and rubella) vaccine has been exceptional at reducing the number of mumps cases in the U.S. Since the pre-vaccine era, there has been a more than 99% decrease in mumps cases in the United States . Overall, two doses of the MMR vaccine are about 88% effective at preventing mumps infection. The Centers for Disease Control and Prevention (CDC) attributes outbreaks of mumps to be a result of a combination of factors - including the effectiveness of the vaccine, lack of previous exposure to wild-type virus, and the intensity of the exposure (such as a college campus) coupled with behaviors or factors that increase the risk of transmission .
What happened in this outbreak?
The majority of cases in the ongoing outbreak in Arkansas have been among school-aged children. In response to the outbreak, Arkansas Department of Health is requiring students with vaccine exemptions for the MMR vaccine to stay home from school for 26 days from the date of exposure and until the outbreak has ended .
A state epidemiologist, Dirk Haselow, MD, PhD, stated that the specific strain of mumps seen in the current outbreak in Arkansas is one of the most genetically distinct from the strain used to create the vaccine. There is speculation that the mumps virus may have evolved enough to make the vaccine less effective , just as we see with the influenza vaccine being a bad fit for a particular flu season.
The outbreak in Arkansas is not a singular event. As of November 5th, six other states have reported more than 100 cases this year: Arkansas, Iowa, Indiana, Illinois, Massachusetts and Oklahoma . There have also been reported outbreaks across the U.S. this year, including the University of Missouri, Yale University, SUNY- New Paltz, and in King County of Washington [5,6,7, 8]. To prevent transmission, the CDC recommends staying away from other people if you are infected, avoiding sharing drinks or eating utensils, disinfecting toys and commonly touched surfaces often, and using general hygiene practices such as washing hands often and covering your mouth and nose with a tissue when you cough or sneeze . In addition to these methods, vaccination remains, by far, the most effective way to prevent transmission and infection.
The war-torn country of Yemen has been battling a significant cholera outbreak since mid-October of 2016. The number of suspected cases doubled over the course of 12 days from 2,070 cases on November 1st, to 4,119 cases on November 13th [2,3,5]. As of November 14th, there has been eight confirmed deaths from cholera and 56 from acute diarrhea across the country (2,5). This cholera outbreak is mostly affecting children, with half of the suspected cases being reported in children under 10 years old [4,6].
What is Cholera?
Cholera is an acute diarrheal disease caused by ingesting food or water contaminated with the bacterium Vibrio cholera, or from coming in close contact with an infected individual. The food or water often becomes contaminated with V. cholerae through fecal contamination from already infected persons . Most people infected with cholera experience mild or no symptoms . Thus, those who are unaware of their cholera infection living in locations with poor water and sanitation infrastructure can contribute to spread of the disease . Cholera more commonly affects individuals living in slums or refugee camps, due to reduced access to clean water and sanitation facilities . Only one in ten people infected with cholera will experience severe symptoms including severe watery diarrhea and vomiting . Consequently, these symptoms cause severe dehydration, which can be deadly. Symptoms often take between 12 hours and five days to occur after ingestion of V. cholerae bacteria . If left untreated, cholera can result in death within hours after symptoms commence .
Cholera is diagnosed through identification of V. cholerae in stool samples [7,8]. Treatment for cholera consists of an oral rehydration solution, which aims to replace the fluids and electrolytes lost as a result of the diarrhea . The oral rehydration solutions consist of sugar and salts that is mixed with clean water for consumption . More severe cases may require intravenous fluid replacement and antibiotics . Treatment must be prompt to avoid death. If immediate treatment is received, the case fatality rate is below 1% .
Prevention of cholera includes adequate water and sanitation infrastructure, adequate hygiene practices, and oral vaccines. According to the World Health Organization (WHO), piped water systems and treatment facilities, water chlorination, water filtration, chemical or solar disinfection of water, safe water storage, and construction of adequate sewage disposal systems are all ways to prevent the spread of cholera at a community level . This infrastructure often takes time to implemented and can be very costly, making it difficult for developing countries to execute and maintain . At the individual level, the WHO suggests appropriate hygiene practices and oral vaccination to prevent cholera . Adequate hygiene practices include handwashing with soap and water, safe preparation of food, and appropriate disposal of feces . The oral vaccination is another method of prevention for cholera. In 2013, the WHO acquired two million doses of these oral vaccinations to control outbreaks in emergency settings . Currently, three oral vaccines exist and all are 65% effective at protecting against cholera . Each type of oral vaccination requires two doses to be the most effective (7). Thus, full vaccination can be difficult to administer in developing countries due to a lack of access and the need for more than one dose.
The Conflict in Yemen
Causes of the War
The current conflict in Yemen began on March 25th, 2015 between a Saudi Arabian-led coalition and the Huthi’s . The Saudi Arabian-led coalition is anti-Huthi individuals in favor of the current President of Yemen, Abd Rabbu Mansour Hadi . The Huthi group is an armed group of individuals who belong to Zayidism, a branch of Shi’a Islam . These Huthi’s are in support of the former President of Yemen, Ali Abdullah Saleh . Approximately 7,070 people have been killed and 36,818 have been injured thus far during this conflict .
Devastating Effects of the Conflict on the Health System
According to a recent article in TIME Magazine, Yemen was ranked the poorest Middle Eastern country prior to the beginning of the conflict . Their economic and health condition of the country has only worsened since the commencement of the conflict. More than 19 million Yemenis lack access to clean water (about 66% of the population), 14 million people are now suffering starvation or malnutrition, and over three million are internally displaced [2,10]. Furthermore, the conflict has had drastic effects on Yemen’s health system. The United Nations released a report stating that only 45% of Yemen’s health facilities are fully functional and that 274 health facilities have been damaged or destroyed due to conflict violence . Shortages of medical doctors and communicable disease management are also occurring as a consequence of the conflict .
Cholera Outbreak in Yemen
Yemen is more adversely impacted by cholera due to a lack of appropriate water and sanitation infrastructure and adequate health facilities – issues exacerbated by the ongoing conflict. The recent cholera outbreak has been spreading at an incredible rate, affecting thousands of people. With limited access to potable water and medical care, cholera is expected to continue infecting people unless something is done. However, due to the ongoing conflict and limited financial support, Yemen has struggled to control the outbreak.
What is being done?
Yemen has limited means to control the outbreak by itself and has received various foreign aid as a result. The WHO has donated one million USD towards response efforts . The Emirates Red Crescent (ERC) has specifically helped the Yemen province, Aden, through the distribution of 20 barrels of chlorine for its water authority and sufficient oral rehydration solution for its hospitals . In addition, UNICEF is assisting in the chlorination of water sources, administering hygiene kits, and informing families about cholera and how to protect themselves .
Despite these efforts to control the cholera outbreak, Yemen still needs to accomplish a lot more to prevent further spread of cholera or other health issues for its civilians. One can only hope that the conflict will end soon so that Yemen can begin its efforts to restoring its country to a peaceful and healthier environment for its civilians.
Just one month after being declared free from the highly pathogenic H5N1 strain of Avian Influenza, India reported several outbreaks of a different strain, H5N8 . The National Delhi Zoological Park in New Delhi reported deaths of nine water birds, including painted storks, ducks and pelicans, which were believed to have migrated locally . In another instance, the H5N8 strain was confirmed in several ducks that died at the Blue Bird Tourist Complex in Hisar, Haryana [3, 5]. Apart from the outbreaks reported in northern states of India, H5N8 outbreaks were also reported in two separate farms in Kerala, a southernmost state in India. 115 birds died on these two farms between 19th October 2016 and 23rd October 2016 . According to the Indian officials, the outbreaks were caused by the same strain, H5N8, found in Punjab, Gwalior and Kerala.
To date, no human cases or deaths from H5N8 strain of avian influenza have been detected, and the World Health Organization concludes that the risk of human infection is low [2,6].
The officials have temporarily shut down the zoo in New Delhi, India. In Kerala, around 21,000 birds were destroyed to contain the spread of the infection to domestic poultry and to human handlers . The control measures applied in the radius of one kilometer around the outbreak locations and included culling an entire poultry population and destroying all poultry products, including eggs, feed, and litter.
Further control measures included restriction on movement of poultry and poultry products, disinfections and cleaning up of infected premises, and quarantine [2,3]. To be prepared for an outbreak in humans, Government of India has stocked up sufficient amount of Tamiflu (Oseltamivir) and has ensured adequate availability of flu masks . The Department of Animal Husbandry has set up biosafety laboratories .
 Government of India. India Declares itself Free from Avian Influenza (H5N1). [Updated: September 14, 2016]. Available from:
As of November 21st, there have been at least 56 outbreaks of H5N8 Highly Pathogenic Avian Influenza (HPAI) in eight countries in Europe and two in the Middle East, just in the month of November alone . Hundreds of thousands of birds have died as a direct result of the virus or through the culling of birds as authorities attempt to curb the spread of the virus. Many different species have been affected, including gulls, geese, ducks, chickens, turkeys, swans, and other types of waterfowl. HPAI outbreaks can have devastating economic consequences due to the massive loss of livestock and the trade restrictions that follow. Large farms in Germany, Hungary, Austria, Israel, and Iran that house thousands of birds have already been affected .
What is Avian Influenza?
Avian influenza, or “bird flu”, belongs to the type A influenza viruses, of which there are many strains that affect a variety of animals, including humans . Type A influenza viruses are subdivided based on two proteins: hemagglutinin (H) and neuraminidase (N). There are 18 different H subtypes and 11 different N subtypes for type A influenza viruses, with many resulting combinations. All but two H and N subtypes have been found in birds . The type A influenza viruses that naturally infect birds are classified as “avian influenza” and it is further separated into two categories based on the viruses’ ability to cause disease in poultry . These categories are low pathogenic avian influenza (LPAI) and high pathogenic avian influenza (HPAI). HPAI causes severe disease and can kill up to 100% of the birds it infects.
While most strains of avian influenza are found to exclusively infect birds, there are some strains such as H5N1, H7N9, and H5N6, which have caused severe illness or death in people . Luckily, H5N8 has not yet been found to cause disease in humans. Although there appears to be a low risk of human infection, the risk is not zero [4, 5]. Influenza A viruses can become virulent to new hosts through a process called antigenic shift . Antigenic shift can happen when two influenza A viruses infect a host and the viruses reassort to form a new virus. For example, if a human were infected with both a human and an avian strain of influenza, a new virus that has genes from both strains could develop to cause disease. This new virus could then become endemic in a population and lead to further reassortments. Natural infections of H5N8 have been reported in dogs in South Korea  and this could provide more opportunities for the virus to eventually mutate into a human-pathogenic strain .
Spread of HPAI H5N8
On September 14, the Food and Agricultural Organization of the United Nations (FAO) released a warning about the spread of HPAI H5N8, when it was found in 17 water birds at Ubsu-Nur Lake in Russia . Despite this early warning, H5N8 spread south into India, affecting several states, and west into Europe. Now, H5N8 has been detected in Hungary, Poland, Croatia, Switzerland, Germany, Austria, Denmark, the Netherlands, Israel, and Iran. Outbreaks in Europe began to be detected in late October . This is the fourth wave of intercontinental movement of HPAI H5 viruses since 2005 and provides incontrovertible evidence that the spread of the virus is due to migratory wild birds . Detections of dead birds infected with H5N8 around Lake Geneva and Lake Neuchâtel on the France-Switzerland border have caused the French Ministry of Agriculture to be on high alert [1, 9]. The deputy head of the World Organisation for Animal Health (OIE) expects more outbreaks in Europe and in the United States, where economic costs of last year’s HPAI (H5N2) outbreak caused losses of $3.3 billion [10, 11].
Poultry farmers have been ordered to keep their animals indoors to prevent any direct contact with possibly infected wild birds or their droppings . However, this may not be enough to prevent H5N8 HPAI spread if additional biosecurity practices are not practiced. HPAI viruses can be spread through contaminated equipment and clothing that comes into contact with infected bird droppings or infected water supplies. It is imperative that farmers do not share their equipment and make sure they are thoroughly decontaminated before entering poultry houses. However, the migratory flyways of shorebirds that potentially carry the virus cover all of Europe and Africa. This may mean that farmers may have to “batten down the hatches” and hope that their poultry do not get infected during the migratory period of these birds.
As of September 2016, there have been 89 cases of Acute Flaccid Myelitis (AFM) across 33 states in the United States (1). There has been a recent spike of cases reported in five counties in Washington State, in which eight children have been hospitalized for AFM. The Washington State Department of Health reported that five children have been released, with three children remaining hospitalized as of November 4th, 2016 (3). The Department of Health is currently investigating the recent surge of cases, but have found no known cause as of yet.
What is Acute Flaccid Myelitis?
AFM is an illness that affects the nervous system, particularly the spinal cord (2). Symptoms of AFM include: facial and eyelid droop/weakness, difficulty moving the eyes, swallowing or speech, loss of muscle tone, and muscle weakness (2). The most detrimental symptom of AFM is respiratory failure, which occurs with the weakening of breathing muscles (2). Patients who experience respiratory failure may require a ventilator machine to help them breathe.
AFM can be caused by a variety of illnesses, such as enteroviruses (polio and non-polio), West Nile virus, and adenoviruses (2). AFM can be diagnosed through magnetic resonance imaging (MRI), testing nerve responses, and testing of cerebrospinal fluid (2). There is no effective treatment or vaccine for AFM. The best way to prevent AFM is by preventing the illnesses that cause it. This includes staying up to date with vaccinations against polio, using protective measures against mosquitoes to prevent West Nile virus, and practicing proper sanitary precautions, like hand-washing (2).
Acute Flaccid Myelitis in the United States
Because 2014 was the first year in which reported cases of AFM have been documented, there remain limitations in the ability to assess trends in AFM. From August to December 2014, there were 120 confirmed cases of AFM (2). These cases occurred simultaneously during an Enterovirus D-68 outbreak (2). However, there were no reported cases of Enterovirus D-68 in 2015 and only a few sporadic cases in 2016, indicating no clear association between Enterovirus D-68 and the recent increase in AFM (2). The cause of the 2014 outbreak remain unknown. In 2015, there were only 21 reported cases of AFM (2). However, reporting of cases are not mandatory in every state, which may affect the representation of the actual number of cases in the United States (2).
While the number of reported cases so far in 2016 is less than in 2014, the Center for Disease Control is still concerned about the recent increase in AFM in the past few months. There is still no known source of this most recent AFM outbreak. What is known is that most of the cases have been children between the ages of 3 and 14 years old and mostly reside in Washington State (1). The Center for Disease Control is investigating this outbreak and will hopefully determine a cause of this cluster of AFM cases.
In September 2015, the first reported case of Mayaro virus was identified in Haiti, marking the first case of the virus to be reported outside of South America. The case, an eight-year-old boy, was concurrently diagnosed with dengue fever. The boy attends a Haitian school that works in partnership with researchers at the University of Florida (UF) to collect blood samples of students that present acute undifferentiated febrile illness, in order to study the transmission of chikungunya in Haiti. The student was initially diagnosed with typhoid based on his symptoms of a fever and abdominal pain, and was treated with the antibiotic co-trimoxazole. The UF researchers tested his blood and it was found to be negative for chikungunya, but positive for dengue virus. When culturing the strain of dengue, the cytopathic changes in the cultured cells induced by dengue occurred at a slower rate than what is usually observed, which suggested either a mutation in the strain, or a co-infection. Further analysis of the sample led the researchers to conclude that the student was infected with Mayaro virus in addition to dengue .
Mayaro virus was first isolated in Trinidad in 1954 . Sporadic outbreaks have been thought to be largely isolated to the northern region of South America. There is also a suggested presence from serologic survey findings in Central America, as can be seen in Figure A1 from the Centers for Disease Control and Prevention (CDC) .
Mayaro virus is in the alphavirus family, among chikungunya virus, dengue virus, and Zika virus. Symptoms of the virus include a febrile illness lasting 3-7 days including chills, headache, nausea, diarrhea, and a maculopapular rash. Additionally, the most notable sign of Mayaro is the debilitating joint pain that can be long lasting (although no permanent damage of the affected areas had been reported thus far) . The virus is transmitted by mosquito, mainly through the Haemogogus genus, which dwell largely in rural settings. However, Mayaro virus has demonstrated vector competence in the Aedes aegypti mosquito, which is also a known vector of chikungunya, yellow fever, and Zika virus, and is found in urban settings .
The similarity in clinical symptoms between Mayaro virus and other more prevalent alphaviruses, like chikungunya, means that Mayaro virus is likely underdiagnosed. Based on findings reported by the CDC, Mayaro virus is actively circulating in the Caribbean region, and there may be a link between the strain in Haiti and the strains circulating in Brazil . For now, there is not cause for concern because the Haitian case may be an isolated incident. The case in Haiti, at the very least, should serve as a warning that Mayaro virus must be closely monitored. Proactive surveillance and precautions could help us avoid another Zika-like outbreak.
On October 19th, the Centers for Disease Control and Prevention (CDC) released an annual report stating that the United States reported a record number of sexually transmitted infections in 2015. The report indicates that approximately 1.5 million chlamydia cases, 400,000 cases of gonorrhea, and 24,000 cases of primary and secondary syphilis were reported last year, reaching a cumulative all-time high for sexually transmitted infections in the U.S. It’s important to note that while the specific STIs did not individually reach all-time highs, the case counts for syphilis, gonorrhea, and chlamydia all reported an increase between 2014 and 2015. The largest increase in reported STI cases came from primary and secondary syphilis, which increased by 19%. This was followed by an increase in reported gonorrhea cases by 12.8%, and a 5.9% increase in reported cases of chlamydia .
Nationally, primary and secondary (P&S) syphilis rates increased in every age group among those aged 15-64 years, as well as in almost every racial and ethnic group during 2014-2015. The P&S syphilis rate among Blacks in 2015 was 21.4 cases per 100,000, which was 5.2 times the rate among Whites (4.1 cases per 100,000). In addition, the P&S syphilis rate increased among both men (18.1%) and women (27.3%) . These rates increased among both sexes in every region of the country during 2014-2015 .
Gonorrhea hit its ultimate lowest rate in 2009, with a reported incidence of 98.1 cases per 100,000. Unfortunately, that number has steadily increased since. During 2014-2015, gonorrhea rates increased in 80% of states, and the District of Columbia. The rate of gonorrhea increased 18.3% among men, and 6.8% among women .
The approximately 1.5 million cases of chlamydia reported in 2015 represents the highest number of annual cases (among nationally notifiable diseases) ever reported to the CDC . There is an apparent disparity in reported chlamydia cases between racial groups. The rate of transmission among Black women was 5.4 times the rate among White women (1,384.8 and 256.7 cases per 100,000 females, respectively) .
Overall, the CDC estimates that STI cases cost the U.S. healthcare system nearly $16 billion each year . The cost will likely increase as the prevalence of antibiotic-resistant STIs becomes greater. Gonorrhea specifically, has been linked to dramatic increases in antibiotic-resistant strains. Between 2013 and 2014, the percentage of gonorrhea samples that showed decreased susceptibility to azithromycin, a common antibiotic, increased by more than 300%, from 0.6% to 2.5% . These dramatic increases in sexually transmitted infections come at a time when health care expenditures are continually increasing, now reaching 17.5% of U.S. GDP. Only 3% of the total healthcare expenditure is spent on prevention efforts . In fact, in recent years more than half of state and local STI programs have had budget cuts, and in effect more than 20 health department STI clinics have closed in one year alone. It is evident this issue will not be disappearing any time soon, which highlights the need for a shift in thinking, from treatment to prevention, in order to effectively combat sexually transmitted infections in the U.S.
On September 30th, the New World screwworm, Cochliomyia hominivorax, was confirmed to be infecting Key deer living in the National Key Deer Refuge in the Florida Keys . This is the first report of a screwworm myiasis cluster affecting multiple animals in 50 years, as self-sustaining screwworm populations were eradicated in the United States by 1966 . This horrible disease has the potential to cause large economic losses for farmers due to potential livestock loss and trade restrictions imposed if the screwworm were to reestablish itself in livestock populations . It can also have devastating effects on wildlife, where surveillance and access to veterinary care is more limited than in production animals. As of October 19th, nearly 10% of the entire population of the endangered Key deer have been humanely euthanized due to infection with screwworm maggots . The Florida Commissioner of Agriculture has declared an agricultural state of emergency in Monroe County and eradication efforts have been implemented to prevent screwworms from spreading to other areas of the United States .
What is New World Screwworm?
C. hominivorax (translates to “man eater”) are flies similar in size to the common housefly but have orange eyes . Gravid females search for hosts on which to lay their eggs - in open wounds or orifices of warm-blooded animals . One female fly can lay up to 400 eggs at a time and eggs hatch within 24 hours into immature C. hominivorax maggots . Unlike other maggots which feed on necrotic tissue, C. hominivorax maggots feed on living tissue . Infestations with these larvae, which resemble screws (hence the name), can cause major damage to soft tissue and even to bone as the larvae use their hook-like mandibles to eat for five to seven days before they detach to pupate . Untreated animals can die within a week or two from secondary infections and/or toxicity as they are literally eaten alive by the screwworm maggots [2, 4].
What are Key deer?
Key deer (Odocoilues virginianus clavium) are the smallest subspecies of the North American white-tailed deer and are the only large herbivore found in the Florida Keys . These endangered miniature deer had a population as low as a few dozen animals in the 1950s but have slightly bounced back since the establishment of the National Key Deer Refuge and the listing of the deer as an endangered species in 1967 . The population had grown to around 1,000 before the screwworm was reported in the refuge on Big Pine Key, approximately 30 miles east of Key West . Adult screwworm flies have now been reported in many of the major Keys that make up the range of the Key Deer . Many of the deer found were so infected beyond treatment that euthanasia was the only option.
Can New World Screwworm infect humans?
Although rare, humans can be susceptible to myiasis from screwworms . An example of such a case in the medical literature, details an event in 2014 of an adult woman in her 20s who was vacationing in the Dominican Republic. After falling asleep on the beach after a night of drinking, she awoke the next day to an uncomfortable sensation of movement in her ear. She removed a fly from her ear and flew home the next day. The discomfort gave way to acute pain and bloody discharge which she initially chalked up to air pressure changes associated with the flight home. A day after returning home, she went to a doctor where many moving screwworms were found in her external ear canal. An otolaryngologist had to manually remove all the larvae, debride the ear canal, and reconstruct the eardrum, which was perforated by the screwworms. During the operation, it was noticed that the larvae permeated the soft tissue in the ear all the way to the temporal bone, luckily without penetrating the middle ear . This is one of many stories that illustrate the severity of screwworms, and the reasons why its reemergence is of major concern. With concerns of local Zika virus transmission, Florida residents and vacationers do not need another disease to be concerned with in the state.
What can be done to control New World Screwworm?
Until recently, New World Screwworms were eradicated from the Southeastern United States since 1957. New World Screwworms were also eradicated throughout Central American countries to the Darien Gap, a nearly untraversable break in the Pan-American Highway, between Panama and Columbia . However, they remain endemic in South America and five Caribbean nations, including the US’s neighbor, Cuba [2, 8]. Eradication efforts success could be primarily attributed to a form of biological control called the sterile insect technique . This technique relies on releasing many male flies that have been sterilized through irradiating screwworm adults and pupae . These sterile male flies mate with multiple female flies. Due to the biology of C. hominivorax, females only mate once in their lifetime. Females that breed with sterile flies get “tricked” into believing they will reproduce and stop mating . These females die without laying eggs, which breaks the life cycle of the screwworm, leading to eventual population decline and collapse [1, 8]. This form of biological control is appealing because it does not rely on widespread use of potentially toxic chemical insecticides. Additionally, sterile insect technique may also prove effective against controlling other vectors, such as Aedes mosquitoes that carry the Zika virus. Sterile fly releases have begun on October 11th in efforts to achieve New World Screwworm eradication again .
If there is one silver lining to this potential catastrophe, the screwworm appears to be localized to the Florida Keys, where there is only one major roadway in and out of the area. A vehicle checkpoint was setup in Key Largo within 48 hours of confirmation of the presence of screwworm and animals that are being driven north into the Florida mainland are being checked for evidence of myiasis . As of October 22nd, over 1,200 animals have been declared negative by agricultural officials . However, a veterinary hospital on Marathon Key, the island just east of the affected area, has treated nine suspected cases of screwworm in pets. These cases consist of three dogs, two cats, two pigs, one rabbit, and one tortoise, indicating the wide range of susceptible species to this disease . Hopefully, this hospital and the highway checkpoint will prevent travelers from unknowingly spreading New World screwworms through the movement of infected animals into the continental United States.
Although human roadway transport of New World screwworm is appearing to be contained, adults can potentially fly great distances and spread this disease to other areas. Adult C. hominivorax flies usually only travel a few miles if there are susceptible hosts present , however some sources report that they can travel up to 125 miles before laying their eggs in a host . While it seems unlikely that an adult fly would travel across the open waters of the Gulf of Mexico, Cuba and Miami fall within this maximum range. There are also many islands within the Florida Keys that an adult may fly to lay its eggs if hosts are present. This could potentially complicate eradication efforts.
The reemergence of the New World screwworm in Florida is a major concern for the livestock industry and the unfortunate wildlife who may become infested with these parasites, especially the endangered Key deer. Infection with screwworm is a terrible situation for any unlucky animal and the disease progression is reminiscent of a horror movie. It is with great hope that eradication of this awful parasite is achieved once again in the United States, and throughout other endemic countries.
In 2012, an estimated 122 of the 223 global cases of polio occurred in Nigeria, more than half of the cases worldwide (1,3). Worldwide efforts to eradicate the poliovirus have come a long way since 2012. Nigeria had not reported any polio cases since 2014, and was removed from the polio-endemic list by the World Health Organization in September of 2015 (4). However, in August 2016, two cases of polio emerged in the Borno state of Nigeria. These two children were paralyzed as a result of contracting the wild poliovirus, which is polio occurring naturally and not due to complications of vaccination. On September 6th, 2016 a third case of the poliovirus in a 24-month old boy was detected (2). This recent emergence of polio cases highlights a substantial setback to the progress of the eradication program in Nigeria over the past several years.
Background on Polio
Polio is a communicable disease caused by poliovirus, of the genus Enterovirus (6). It is transmissible from person-to-person through contact with feces or droplets from a sneeze or cough from an infected person (6). Polio primarily affects children under the age of three, but can potentially infect anyone (7). About 72 out of 100 people infected with poliovirus do not exhibit any symptoms (6). One out of four people infected with the virus will experience flu-like symptoms including fever, sore throat, upset stomach, headache, and fatigue (6). Less than 1% of people infected with the virus experience paralysis, which can cause death if the paralysis affects muscles that are necessary to help them breathe (6,7).
Poliovirus is preventable through vaccination. The two types of vaccination that exist are inactivated polio vaccine and modified-live, oral polio vaccine (7). As a result of these prevention measures, all countries in the world have been deemed “polio-free” from wild poliovirus except for Afghanistan, Pakistan, and most recently, Nigeria (1).
Nigeria was on the brink of polio eradication. The last reported case before the summer of 2016 was two years ago in July of 2014 (1). Yet, unfortunately, the recent cases of polio in Nigeria occurred just short of when the Global Polio Eradication Initiative (GPEI) was going to announce Nigeria as polio-free in 2017, which occurs when there are no polio cases for at least three years. (8). Now, with the recent outbreak, Nigeria will not be certified as polio-free until at least 2019 (8).
There have been two significant barriers to the eradication of poliovirus in Nigeria. The first major obstacle to eradicating the disease has been the instability and insecurity of the Northern regions under the control of Boko Haram, a Nigerian Islamist terrorist group. The terrorist group has publicly advocated against the usage of vaccinations claiming that it is a “Western plot” against Nigerian children (3). They have continuously made it extremely difficult for vaccination teams or government health officials to enter into their territories to vaccinate their hard-to-reach child populations over the past few years (3). As a result of Boko Haram’s efforts, half a million children did not receive the polio vaccination in the Northern regions (9). Not surprisingly, the most recent 2016 polio cases have been children from the Borno region and the border of Chad, two of the Northern regions, previously controlled by the terrorist group (9).
The insecurity of the Northern regions of Nigeria has also interrupted adequate surveillance of the disease, the second major impediment to eradicating polio. The insufficient surveillance of polio has enabled the disease to go undetected. According to the United States Center for Disease Control, two of the most recent cases were of a viral strain similar to one last seen in 2011, indicating that the virus had likely been circulating undetected for years (2,10). This new information sheds critical light on the ability of polio to remain undetected rather than to re-emerge. It is essential that governing bodies of the polio eradication efforts take this into consideration for future control endeavors. Some polio experts are rethinking labeling a country as “polio-free” after only three years given this recent discovery. Respectively, polio eradication workers are hoping to use this current situation in Nigeria as a “wake-up call” to ensure that future polio eradication campaigns be executed with better long-term surveillance plans (2,10).
What is Being Done Now
The government of Nigeria is addressing this outbreak with plans of vaccination campaigns. The government plans to vaccinate about five million children in the next few weeks (5). With recent military action, many communities in the Northern territories of Nigeria are now liberated from Boko Haram’s control (3). This enables vaccinators to enter these previously inaccessible territories and making it easier to reach the government’s vaccination goal. However, Nigeria still plans on vaccinating children under five who remain in unstable, terrorist-controlled, areas. The campaigns are airlifting vaccinators via helicopter to these unstable areas to avoid usage of unsafe roads (10). To help Nigeria accomplish its goal of five million vaccinated children, the World Health Organization is deploying some of its staff and polio eradication resources (11). Additionally, the GPEI is providing Nigeria with significant support as a result of this recent outbreak (11).
Nigeria is doing everything that it can to contain and prevent further spread of the wild poliovirus. One can only hope that these vaccination campaigns will be enough to see the last of the poliovirus in all of Africa.