#DDD3: Day Two Recap

May 22, 2015 | Colleen Nguyen | Commentary

#DDD3: Day One Recap

May 21, 2015 | Colleen Nguyen | Commentary

Dengue Epidemic in Brazil

May 13, 2015 | Noushin Berdjis | Outbreak News

 The Brazilian Ministry of Health has reported 746,000 registered cases of Dengue fever and 229 confirmed deaths since January 2015 [1,3]. This marks a 234% increase in Dengue cases and a 45% increase in Dengue deaths since the previous year [3]. Although nine states are currently experiencing an outbreak of Dengue, more than half of these cases occurred in São Paulo, which also happens to be Brazil’s most populous state [1]. To date, São Paulo has had three times as many Dengue cases as there were reported in 2014 [1].

 

Dengue Fever

Dengue fever is a viral disease transmitted to humans through the bite of an infected female mosquito [1-5]. Dengue can be found in tropical and sub-tropical climates across the globe, primarily in urban and semi-urban areas [5]. This places about half of the world’s population at risk [5]. The incubation period for Dengue fever is 4 to 10 days [5]. Symptoms last about 2 to 7 days and include: high fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, and swollen glands [1-5]. Dengue Hemorrhagic Fever (DHF) is a potentially deadly complication that can arise from a Dengue infection [5]. Symptoms of DHF, also known as Severe Dengue, include severe abdominal pain, rapid breathing, persistent vomiting, and bleeding gums [5].

 

Since there is currently no specific treatment or vaccine against Dengue, vector control is the most effective prevention method [5]. The primary Dengue vector in South America is the Aedes aegypti mosquito [2,5]. The Aedes aegypti mosquito is also capable of transmitting Yellow Fever and Chikungunya [2]. These mosquitoes are daytime feeders that prefer urban habitats, bite multiple humans during each feeding period, and breed primarily in man-made containers such as water tanks, plastic bottles, discarded tires, and flower pots [1-2,5]. An infected mosquito is capable of transmitting the virus for the remainder of its life [5].

 

Outbreak in Brazil

Dengue has been endemic in Brazil since its re-emergence in 1981 [1]. Cases typically increase during the peak of the rainy season, which lasts from January to May [2,4]. However, this year’s rainy season in Brazil has been particularly dry, resulting in severe drought throughout much of the country [2]. São Paulo, for example, has been facing the worst drought in decades [2]. As a result of the drought, people have been storing water in large, open containers. These containers are an ideal breeding ground for the Aedes aegypti mosquito, resulting in a proliferation of mosquito populations [2]. This increase in Dengue vectors results in increased transmission of the virus to humans. The increased prevalence of the disease among humans will also increase transmission. As a result of the drought, São Paulo has reduced the flow of water in several of the major water pipes throughout the city [2]. This has resulted in a decrease in access to running water for thousands of people and an increase in the use of home water tanks [2].

 

What is Being Done?

Hospitals in São Paulo have been overburdened with the large number of Dengue cases. Therefore, “Dengue tents” have been set up to treat patients in high-risk areas within the city [4]. Additionally, 2,500 health officials have been tasked to go door-to-door and educate residents on preventive measures, such as filling potted plants with sand, keeping containers dry and swimming pools covered, as well as placing mosquito nets over open water tanks [2,4].  This mass educational campaign has had limited success because individuals are wary about opening their doors to strangers [4]. As a result, the mayor of São Paulo has recruited soldiers who have been trained to go door-to-door and provide education on proper mosquito control, water storage, and effective repellant and insecticide use [4]. The hope is that the public will be more trusting and receptive toward the army, resulting in greater cooperative with the health officials and their educational messages [4].

 

Brazilian health authorities announced on May 5th, that they believe the outbreak has reached its peak. The weather is beginning to change and becoming less favorable for the mosquitoes [1]. Additionally, Brazil is currently testing three Dengue vaccines and hopes to have an effective vaccine available to the public by 2016 [6].

 

Sources:

  1. http://www.bbc.com/news/world-latin-america-32589268
  2. http://www.wsj.com/articles/drought-stricken-sao-paulo-battles-dengue-fever-outbreak-1425420508
  3. http://outbreaknewstoday.com/dengue-cases-rise-in-brazil-as-does-dengue-spending-90861/
  4. http://www.wsj.com/articles/brazil-city-calls-in-army-to-fight-dengue-1429292950
  5. http://www.who.int/mediacentre/factsheets/fs117/en/
  6. http://sbmt.org.br/portal/vacina-contra-dengue-deve-estar-disponivel-no-brasil-ate-2016/?lang=en

 

Dog Found to be Source of Colorado Plague Outbreak

May 11, 2015 | Marie Killerby and Emily Cohn | Outbreak News

Recently, the Centers for Disease Control (CDC) reported that in July 2014 a Colorado man contracted plague from his dog [1]. Furthermore, three other persons who had come into contact with the dog, and one of whom also had contact with the owner, were confirmed positive for plague [1]. All four human cases were treated with antibiotics and made a full recovery [1]. As one individual had contact with both the owner and the dog, it is possible that human-to-human transmission of the plague could have occurred, but this has not yet been confirmed [1]. After this cluster of human infections the CDC highlighted the need to consider plague as an infection of domestic animals in endemic areas [1].

 

What is plague?

Plague is a zoonotic disease cause by the bacterium Yersinia pestis. It is the same bacterium responsible for the “Black Death” in the 14th century where it was claimed to have killed 60% of the European population [2]. The bacterium predominantly exists in rodents, and is transmitted by rodent fleas (or contact with infected tissues) from one rodent to another [3]. In certain rodent species plague continuously cycles between rodents without causing many deaths, enabling the bacterium to exist continuously in the population, known as the enzootic cycle [3]. Other species can catch plague but they tend to die out - for example in rabbits and susceptible rodents, mortality rates can approach 100% [4]. Humans can become infected from animals via bites from rodent fleas, contact with infected tissue, or inhalation of infectious droplets [3]. Humans can also transmit plague between one another if they develop the pneumonic form of the disease [5].

 

Where does plague exist?

Plague exists across many regions of the world, but most human cases within the last 25 years have occurred in Africa [6]. Within the United States, most plague causes occur in northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon and western Nevada [6]. A variety of different wildlife reservoirs exist across the United States, including prairie dogs, ground squirrels, antelope ground squirrels, chipmunks, woodrats and mice. [4]. The principle vectors for plague include prairie dog fleas, ground squirrel fleas and various species of woodrat and mouse fleas. [4]. Despite the abundance of potential reservoir hosts, human cases in the United States are rare; In recent years there has been on average only seven cases of plague per year in humans [4].

 

What are the symptoms?

 In humans, three main forms of plague infection occur: Bubonic plague, which is characterised by fever and swollen lymph nodes, septicemic plague, characterised by fever, chills, abdominal pain, shock, and possibly bleeding, and pneumonic plague with fever, weakness and pneumonia (inflammation of the lung tissues) [5]. Pneumonic plague is the only form transmissible from person to person, this occurs via coughing and sneezing of infected droplets [5]. Over 80% of United States plague cases have been the bubonic form, which makes transmission less likely [6]. Plague is treatable with commonly available antibiotics [7], however deaths still occur across the world [6].

 

In dogs, plague usually causes a mild illness with self-limiting fever and swollen lymph nodes, with dogs often becoming infected via eating infected rodents [8]. The canine case in this report showed an unusually severe form of the disease with fever, difficulty in breathing and coughing up blood, before being humanely euthanized [1].

 

Are you or your pets at risk?

Although dogs can catch and transmit plague, they are less likely to do so than cats, which are highly susceptible to the disease [8]. It is thought that whilst some cats may become infected through flea bites, the more common route is through ingestion of infected rodents [8]. Cats show more severe clinical signs than dogs and can develop bubonic, septicemic and pneumonic forms [8].  Cats with pneumonic plague pose the highest risk to humans as they can transmit pneumonic plague via coughing and sneezing of infectious droplets [8]. From 1977 to 2006, 29 people in the United States were diagnosed with cat-associated plague and at least five of these patients developed pneumonic plague [8]. Overall plague is a rarely contracted by people in the United States but it is worth remembering that both cats and dogs can potentially transmit infection via bites, scratches, owner contact with infected fluids, or pets transporting infected fleas into the house [9].

 

Prevention

Although contracting plague from your pet is very unlikely, there are steps that can be taken to minimize the risk. In order to prevent your dog or cat becoming infected from fleas, the CDC recommends that If you live in areas where plague occurs, treat pet dogs and cats for flea control regularly and do not allow these animals to roam freely [9]. The CDC also recommends performing rodent control measures, taking any ill animals (especially cats) to a veterinarian, using repellent if you think you will exposed to rodent fleas when outdoors in an endemic areas, and avoiding contact with sick or dead animals [9, 10]. Finally, it is important that veterinarians and physicians in endemic areas are aware of both cats and dogs as a potential source of infection.

 

  1. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6416a1.htm
  2. http://www.cdc.gov/plague/history/index.html
  3. http://www.cdc.gov/plague/transmission/index.html
  4. https://www.avma.org/News/Journals/Collections/Documents/javma_222_4_444.pdf
  5. http://www.cdc.gov/plague/symptoms/index.html
  6. http://www.cdc.gov/plague/maps/index.html
  7. http://www.cdc.gov/plague/diagnosis/index.html
  8. Abbott, R.C., and Rocke, T.E., 2012, Plague: U.S. Geological Survey Circular 1372, 79 p., plus appendix, available at http://pubs.usgs.gov/circ/1372/pdf/C1372_Plague.pdf
  9. http://www.cdc.gov/plague/healthcare/veterinarians.html
  10. http://www.cdc.gov/plague/prevention/index.html
Nigeria Mystery Outbreak Solved

Apr 29, 2015 | Noushin Berdjis | Outbreak News

On April 13, 2015 an outbreak of a mysterious disease began in Ondo, Nigeria [1-6].  By April 16, the unknown disease spread swiftly across the Ode-Irele community within Ondo, resulting in a total of 25 cases and 18 deaths [1-6]. All cases were male and between the ages of 22 and 75 years of age [1,5]. The remaining five cases are currently being treated at the University College Hospital in Ibadan, Nigeria [1]. Symptoms of this mysterious disease include the rapid onset of a severe headache and blurred vision, followed by sudden blindness, loss of speech, unconsciousness and sudden death – all happening within 48 hours of symptom onset [1-3,5].  

Naturally, such an outbreak has caused a great deal of panic within the Ondo-Irele community [4]. Community members initially suspected Ebola, but this was quickly repudiated. Health officials believed the mystery disease was unlikely to be Ebola because the cases were not showing the classic Ebola symptoms of diarrhea and vomiting. This belief was confirmed when laboratory tests came back negative for Ebola [4,6]. 

The World Health Organization (WHO) was notified on April 15 [6]. Preliminary reports from the WHO stated that a cluster of cases with rapid symptom onset and disease evolution is suggestive of poisoning, rather than an infectious pathogen [6]. Consequently, the WHO initially speculated that this mystery outbreak was the result of pesticide poisoning [1,6]. Post-mortem test results have confirmed that the cause of deaths were not due to an infectious agent [3].

The Nigerian government has since released a statement indicating the cause of this mystery outbreak as methanol poisoning [1].  

 

Methanol Poisoning

Post-mortem toxicology results have shown that the 18 confirmed deaths were in fact due to methanol poisoning [1-3,5]. Epidemiologists were able to link the outbreak to the consumption of a local alcoholic beverage, “Ogogoro” [1,6]. The locally brewed beverage, consisting of gin, local roots and other herbs, was contaminated with methanol [1-3,5-6]. The WHO discovered that 71% of the cases had consumed this locally brewed gin [6].

Methanol is a toxic alcohol used primarily for industrial and automotive purposes [7]. The active ingredient, methyl alcohol, is colorless, flavorless and odorless, but is extremely poisonous if ingested or inhaled by humans [7]. Methanol poisoning can occur from consuming informally made or “home-brewed” alcoholic beverages contaminated with methanol [6-7]. Improperly distilled liquor can lead to the production of Methanol. Methanol poisoning and symptoms occur as a result of methanol’s metabolic by-products [7]. These by-products cause acidosis or the accumulation of acid within the blood, which results in drowsiness, confusion, and blindness [7]. As the acid accumulates in the blood, the toxicity worsens, becoming more severe as time goes on [7]. If left untreated, methanol poisoning quickly leads to death.

On Monday, April 27, 2015 the Nigerian government stated that the poisoning cluster is currently under control [1]. Fidelis Nwankwo, Nigeria’s Minister of State for Health, stated that there have been no deaths in the past 72 hours and no new cases in 100 hours [1-2,5]. Methanol may have been present in “Ogogoro” due to the unregulated distillation process for home-brewed alcohol or because of the deliberate addition of methanol to increase the gin’s potency [6]. A similar methanol poisoning outbreak occurred in Mozambique in January 2015, resulting in over 73 deaths [6]. The government has since advised residents against consuming “Ogogoro” [1].

 

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Sources:

  1. http://www.premiumtimesng.com/news/headlines/181774-nigerian-govt-says-ondo-strange-disease-under-control-blames-methanol-poisoning.html
  2. http://pulse.ng/health/ondo-mystery-disease-local-gin-consumption-caused-disease-outbreak-fg-who-allege-id3684748.html
  3. http://pulse.ng/health/in-ondo-strange-disease-not-contagious-tests-show-ethanol-poisoning-health-comm-id3669876.html
  4. http://saharareporters.com/2015/04/16/infectious-disease-outbreak-kills-over-25-ondo-health-officials-claim-it-not-ebola
  5. http://www.tribune.com.ng/news-headlines/item/34188-ondo-outbreak-not-due-to-ebola-infectious-organism-fg/34188-ondo-outbreak-not-due-to-ebola-infectious-organism-fg
  6. http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4609-unknown-in-ondo-state-nigeria.html
  7. http://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750029.html

 

Powassan Emerges in Connecticut

Apr 19, 2015 | Noushin Berdjis | Outbreak News

Researchers recently found Powassan virus infected ticks in Bridgeport and Branford, Connecticut [1, 5-6]. Although the virus had already been reported in neighboring states -- New York, New Jersey, Massachusetts and Maine -- it had not yet been found in Connecticut [4]. There have been no reported human infections of Powassan virus in Connecticut, but Dr. Theodore Andreadis from the Connecticut Agricultural Experiment Station, warns that human cases will soon follow [4]. Dr. Andreadis and his team are currently conducting a study of ticks to determine the prevalence of the virus within the state [4].

 

What is Powassan Virus & Why the Alarm?

Powassan Virus is an emerging infectious disease related to the West Nile virus. Its life cycle requires transmission between certain rodents and specific species of ticks [2]. The virus can be transmitted to humans through the bite of an infected tick [1-6]. Similar to West Nile Virus, humans are a dead-end host for the disease [2]. This means that if an uninfected tick bites an infected human, the tick will not become infected. This is because the concentrations of the virus in the human’s bloodstream are not high enough for a feeding tick to become infected. The incubation period is highly variable, spanning from one week to one month [1,2]. Although not all infected individuals show signs of infection, common symptoms include headache, fever, vomiting, confusion, seizures, and memory loss [1,2]. Powassan virus can also infect the central nervous system, resulting in serious neurological diseases such as encephalitis (inflammation of the brain) and meningitis (inflammation of the brain and spinal cord membranes) [2,5-6].

So why are health authorities worried after discovering virus-infected ticks in Connecticut?

Apart from the fact that the disease had never been seen in Connecticut, people are worried because there is no available vaccine and no medical cure for the Powassan virus [1-6]. Furthermore, unlike Lyme disease where the infected tick needs to feed for at least 24 hours before infection can occur, with Powassan virus, the tick only needs to feed for one to two hours for the virus to be transmitted [2,6]. Health officials are also concerned because roughly 10% of Powassan virus encephalitis cases end in death and approximately 50% of infected individuals will have permanent neurological symptoms [2,6]. These include recurrent headaches, muscle wasting, and memory loss [1-2]. Lastly, although the disease is rare, there has been an increase in reported cases within the Untied States over the past few years [2,6].

 

Prevention

In the United States, Powassan Virus is primarily found in the northeastern states and the Great Lakes region [2]. Since the disease is spread by ticks, cases occur in late spring and early summer, when ticks are most active [2]. Therefore Connecticut residents and visitors should be extra cautious of tick bites during the warmer months of April through September.  

Prevention methods are similar to those for mosquito-borne diseases. This includes avoiding contact with ticks, wearing protective clothing (long sleeves and pants), using repellents, and conducting thorough tick-checks following outdoor activities [2,5]. The CDC provides detailed instructions on how to properly remove an embedded tick [3].

 

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Sources

[1] http://newyork.cbslocal.com/2015/04/07/non-treatable-virus-found-in-ticks-in-southern-connecticut/

[2] http://www.cdc.gov/powassan/

[3] http://www.cdc.gov/ticks/removing_a_tick.html

[4] http://www.nbcconnecticut.com/news/local/Powassan-Virus-Tick-Borne-Deadly-Fatal-Disease-Branford-Bridgeport-299369551.html

[5] http://time.com/3817208/powassan-virus-ticks-lyme-disease/

[6] https://www.yahoo.com/health/powassan-virus-in-connecticut-ticks-should-you-be-116051450152.html

Rubella in Taiwan: Second Case Confirmed

Apr 17, 2015 | Yuki Ara | Outbreak News

On March 18th, a female flight attendant was confirmed to be infected with rubella in Taiwan [1].  Before she developed symptoms, she had a travel history that included Vietnam, Indonesia, and Hong Kong [1]. After her confirmation, she was determined to be the first imported case of rubella in Taiwan this year, though the second confirmed case of rubella in the country overall, this year.

Prior to this imported case, the first case of rubella was reported on January 29, 2015 [2]. A 41-year-old male who resided in northern Taiwan was confirmed of rubella infection. Since he did not have a history of traveling outside of the country, Taiwan Centers for Disease Control (Taiwan CDC) determined his case of rubella as an indigenous one.

Health officials have identified close contacts to these cases and have placed them under monitoring. None of the first case’s contacts tested positive and the second case’s contacts were monitored until April 11th to ensure the prevention of any further outbreaks. More than 1500 people are followed for the flight attendant’s case and it has set a new record for the Taiwan CDC’s monitoring list [3]. 

In Taiwan, the average number of rubella cases tend to be small for these years, though the years 2007, 2008, and 2011 seem to be exceptions. These increase in cases for those years coincided and were often linked with the increase in rubella cases of other countries in Asia for those years [4]. In 2014, there were seven cases in Taiwan and six of the seven cases were imported [4, 5]. Yet, these numbers still seem to be limited compared to other countries in Asia [6].  

 

About Rubella

Rubella is caused by a virus [7]. Symptoms of rubella infection include mild fever, rash in the face and body, swollen lymph nodes in the neck or behind the ears [7]. Further, there may be body aches, fatigue and coughing, as well as other symptoms that may resemble a common cold [7]. It is highly contagious and is transmitted through close contact with an infective case [7].

However, rubella infection is preventable through vaccination. A live attenuated rubella vaccine was introduced to Taiwan in 1986, mandated for female junior high school students [8]. In 1992, Taiwan CDC expanded to a more universal vaccination program providing Measles-Mumps-Rubella (MMR) vaccines to 15 month old children [8]. Since 2001, Taiwan CDC provides the second dose regularly for children at seven years of age before they enter school [8]. MMR vaccine coverage in Taiwan is approximately 95% among the general population [8].

 

Rubella & Pregnancy

Pregnant women are unable to receive vaccination during pregnancy, so it is strongly encouraged to take a blood test and see if they have enough rubella immunity [9]. It is also encouraged to wait at least a month after the vaccination to become pregnant [9].

If women who are not vaccinated or have low antibodies contract rubella during pregnancy, especially during the first trimester, the fetus may also have a chance of contracting the virus and congenital rubella syndrome (CRS) may occur [10]. Babies with CRS may have birth defects such as eye abnormalities, congenital heart disease, mental disabilities, and organ damage. Worldwide, more than 100,000 babies are born with CRS every year [10]. In Taiwan, due to effective vaccination programs, only five cases of congenital rubella syndrome (CRS) have been confirmed from 1994 to 2008 [8]. Four out of five patients’ mothers were foreigners. No confirmed CRS cases have been reported since 2009 [8].

 

Why Vaccination Matters

Although vaccine coverage in Taiwan is high, there is always risk of rubella resurgence due to several factors. First, there is frequent travel amongst the population, so there will always be risk of an imported case from countries with lower vaccination coverage [11].  According to the WHO, global coverage of rubella vaccine is approximately 44% in 2013 which indicates, there still are countries with lower coverage compared to other regions in the world [12]. Second, Taiwanese who were born before the country’s universal vaccine program started, are susceptible to rubella infection due to not being vaccinated. This so-called a “vaccine gap” was also one of the factors behind the rubella outbreak in Japan in 2013 [13, 14]. Third, although the vaccine coverage at the country level is high in Taiwan, there are communities with less than enough vaccine coverage (at least 80% of vaccine coverage is necessary to prevent a rubella outbreak) remain at risk of an outbreak [4, 15]. Further, MMR vaccine is effective after the first dose. The second dose assures another chance to achieve immunity for people who did not achieve immunity the first time around. If people miss receiving the second dose, some of them may also be susceptible [15].

Therefore, not only having a high percentage but maintaining high vaccination coverage is considered important. The advantage of the rubella vaccine is that although there are several genotypes of rubella virus, they share a common serotype so the current used vaccine is considered effective [16]. There may be a possibility of mild adverse events such as fever, mild rash, or swelling in the cheeks or necks, but severe adverse events are rare [15, 17]. Taiwan CDC is encouraging people who are susceptible to receive MMR vaccine and to maintain vigilance as new cases arise [4, 10]. 

 

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Sources

[1] http://outbreaknewstoday.com/taiwan-flight-attendant-is-countrys-2nd-rubella-case-contact-tracing-ongoing-76925/

[2] http://outbreaknewstoday.com/taiwan-reports-years-first-indigenous-rubella-case-31708/

[3] http://www.taipeitimes.com/News/taiwan/archives/2015/03/20/2003613987

[4] http://nidss.cdc.gov.tw/en/SingleDisease.aspx?dc=1&dt=2&disease=056

[5] http://www.cdc.gov.tw/english/info.aspx?treeid=BC2D4E89B154059B&nowtreeid=EE0A2987CFBA3222&tid=46B4CC320AE574DC

[6] http://apps.who.int/immunization_monitoring/globalsummary/timeseries/tsincidencerubella.html

[7] http://www.cdc.gov/rubella/about/index.html

[8] http://www.cdc.gov.tw/english/info.aspx?treeid=e79c7a9e1e9b1cdf&nowtreeid=e02c24f0dacdd729&tid=F53EF5695666723D

[9] http://www.cdc.gov/vaccines/adults/rec-vac/pregnant.html

[10] http://www.cdc.gov/vaccines/pubs/surv-manual/chpt15-crs.html

[11] http://focustaiwan.tw/news/asoc/201501300021.aspx

[12] http://www.who.int/immunization/monitoring_surveillance/global_immunization_data.pdf?ua=1  

[13] http://theconversation.com/vaccination-gaps-led-to-rubella-outbreaks-in-japan-and-poland-15970

[14] http://www.nih.go.jp/niid/en/iasr-vol34-e/865-iasr/3469-tpc398.html

[15] http://www.who.int/wer/2011/wer8629.pdf?ua=1

[16] http://idsc.nih.go.jp/iasr/32/379/tpc379.html

[17] http://www.cdc.gov/vaccines/hcp/vis/vis-statements/mmr.html

Canine Influenza in Chicago

Apr 15, 2015 | Marie Killerby Colleen Nguyen | Outbreak News

Chicago has recently seen an increase in cases of canine influenza. Cook County Department of Animal and Rabies Control issued a warning earlier this month for dogs to avoid areas where other dogs may congregate [1]. So far, the outbreak has resulted in the death of five dogs, sickened many more, and has caused closures of a local dog park and pet hotels [1,2,3].

You may or may not be surprised that dogs catch influenza, as we sometimes associate flu with other animals such as birds and pigs. However, whilst the media are announcing that ‘canine influenza virus is nothing new’, within the history of the flu virus, dogs becoming infected with flu is a relatively recent phenomenon [4]. The first canine influenza virus, a H3N8 strain, was detected in racing greyhounds in 2004 and was thought to have passed from horses to dogs [5]. Prior to this incident, the same virus is thought to have existed in horses for over 40 years [5]. Even more recently, another flu virus, the H3N2 strain, was detected in dogs in South Korea and China in 2006 [6]. This strain is thought to have passed from birds to dogs [6]. Whilst the current outbreak in Chicago was originally thought to be the H3N8 strain already found in North America, further testing by scientists have revealed the outbreak strain to be the H3N2 strain, which originally emerged in Asia in 2006 [6]. After this revelation, further investigations will likely take place to locate how this particular strain infected dogs in Chicago.

 

Zoonosis

So, which other species can get flu viruses and how do they pass between species? Many different non-human animal species can get influenza viruses, including ducks, chickens, pigs, whales, horses, and seals [7]. Wild waterfowl, however, are the natural carriers of the virus, and the virus can naturally live in their intestines without the birds getting sick [8]. Therefore, the influenza virus is thought to have originally existed in these birds and ‘jumped’ to other species from there. Influenza viruses can pass from one species to another on close contact between a sick animal and a new species. However, even with close contact, it is very unlikely that the influenza virus will cause an infection in a new species. The reason? Flu viruses are usually well adapted to infecting and spreading between members of the same species, but are not as well-adapted to infect a different species. This is why people commonly catch flu from each other but only very rarely catch influenza from other animal species.

 

What Does This Mean?

Dogs with canine influenza are therefore very unlikely to pass it to humans. In reference to H3N8 canine influenza, the Center for Disease Control (CDC) states that ‘there is no evidence that this virus infects humans’ [5]. Also, in the 40 years that the H3N8 virus has been present in horses, no humans have ever been observed to become ill from the equine influenza virus [9]. However, other strains of the H3N2 virus have been passed from pigs to humans and then shown limited human-to-human transmission, so this canine influenza virus may pose a higher risk of dog to human transmission than previously thought [10]. Whilst it is very unlikely, it isn’t impossible that canine influenza could infect people, so scientists, doctors and veterinarians should remain vigilant to this possibility.

As for dogs, if you are concerned about your dog becoming infected with canine influenza, there is a vaccination available. However, this vaccination was developed to protect dogs from the H3N8 strain, so there is some concern over how effective this vaccination will be in preventing dogs catching the H3N2 strain circulating in the current outbreak [6]. As a result, dog owners in the outbreak area should be wary of their dogs mixing with other dogs and should call their veterinarian if they notice any of the symptoms of canine influenza: cough, runny nose or fever [5].

 

 

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Sources

[1] http://www.chicagotribune.com/news/local/breaking/ct-dog-flu-deaths-met-0404-20150403-story.html

[2] http://www.chicagotribune.com/suburbs/daily-southtown/news/ct-sta-evergreen-dog-park-st-0409-20150408-story.html

[3] http://www.chicagotribune.com/business/breaking/chi-petsmart--dog-flu-20150403-story.html

[4] http://wgntv.com/2015/04/03/outbreak-of-dog-flu-hits-chicago-area/

[5] http://www.cdc.gov/flu/canine/

[6] http://mediarelations.cornell.edu/2015/04/12/midwest-canine-influenza-outbreak-caused-by-new-strain-of-virus/

[7] http://www.cdc.gov/flu/avianflu/virus-transmission.htm

[8] http://www.cdc.gov/flu/avianflu/avian-in-birds.htm

[9] http://www.oie.int/doc/ged/D14001.PDF

[10] http://www.cdc.gov/flu/swineflu/h3n2v-cases.htm

Nipah in Bangladesh

Apr 12, 2015 | Colleen Nguyen | Outbreak News

According to the Bangladesh Institute of Epidemiology, Disease Control and Research (IEDCR), as of February 2015, nine cases of Nipah virus have been recorded across the country [1]. The reported cases stem from six districts – Nilphamari, Faridpur, Magura, Ponchoghor, Naugaon, and Rajbari [1]. Case analysis reveals that 56% of recent cases have been male, with the median age across those infected, as 15 years of age [1].

A History of Nipah Virus

Nipah virus (NiV) was isolated and identified for the first time in 1998, when pig farmers and individuals who had close contact with pigs, became ill with encephalitis and respiratory illness in Malaysia and Singapore [2,3]. The first outbreak took place in Kampung Sungai Nipah, Malaysia – a location for which the virus would be named after [3]. The first outbreak produced only mild disease in pigs, but resulted in approximately 300 human cases, with 100 fatalities [2]. Case fatality for Nipah in general is estimated to be between 40% to 75%. However, the World Health Organization (WHO) highlights that this rate may vary depending on surveillance capacities involved in the outbreaks [1].  Since the first outbreak, there have been no intermediate hosts associated with subsequent outbreaks – that is, no pigs were linked to human infections. A CDC study discovered that human infections have been due to the consumption of virus-contaminated date palm sap [3,4]. 

NiV is part of the family Paramyxoviridae, within the genus Henipavirus [2]. Scientists have since traced NiV back to Indian flying foxes, a type of fruit bat found across southern Asia [4]. Date palm sap happens to be a delicacy sought after by both bats and humans [4]. The sap is collected from date palm tree trunks. The trees are tapped using machetes and the flowing sap collected into clay pots overnight [4]. At night, when the bats forage for food, they sometimes drink the sweet sap collected in the pots, and subsequently contaminate the sap with NiV through their bodily fluids, such as saliva, feces, or urine [4]. The unknowingly-contaminated sap is then sold at markets, where direct consumption of NiV results in the spread of the virus through local populations [4].  

Preventive Measures

There is no treatment or vaccine for NiV, so preventive measures are of critical importance for protection against infection [1].  Cooking or fermenting palm sap can destroy the virus, but most sap sold at markets is often sold and consumed raw [4]. Therefore, avoiding palm sap completely can prevent NiV infection. Additionally, people can avoid exposure with ill pigs and bats in areas considered to be endemic with NiV [5]. Efforts that include enhanced surveillance systems, increased public awareness, and interventions including the use of bamboo screens on top of the palm sap pots, can also prevent future outbreaks [5,6].

 

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Sources

[1] http://outbreaknewstoday.com/bangladesh-reports-nine-nipah-virus-cases-to-date-in-2015/

[2] http://www.cdc.gov/vhf/nipah/

[3] http://www.who.int/csr/disease/nipah/en/

[4] http://science.kqed.org/quest/2014/05/27/sweet-and-deadly-bat-borne-virus-brews-in-bangladeshs-date-palm-pots/

[5] http://www.cdc.gov/vhf/nipah/prevention/index.html

[6] http://www.ncbi.nlm.nih.gov/pubmed/22669914

Ross River Virus Strikes Brisbane

Apr 8, 2015 | Noushin Berdjis | Outbreak News

Brisbane, Australia is currently the epicenter of the largest outbreak of Ross River Virus the country has experienced since 1996 [2]. As of March 14th, there have been 2,835 cases since January 1, 2015 [2]. This is approximately 500 more cases than were seen in the previous year [2].

 

About Ross River Virus

This vector-borne disease is primarily found in Australia, Papua New Guinea, parts of Indonesia, and the western Pacific Islands [1].  Ross River Virus (RRV) is spread indirectly, through the bite of an infected mosquito. This means that the virus cannot be spread through person-to-person contact. Animals such as wallabies and possums are the natural reservoir for the virus [2]. When a mosquito bites an infected animal, it becomes a vector and is capable of passing the virus to humans through an infectious bite [1,2]. The incubation period for RRV is 7 to 14 days, and common symptoms include swollen joints (primarily the ankles, fingers, knees, and wrists) and muscles. Other symptoms include fever, fatigue, headache, swollen glands, as well as rash [1].

Currently, there is no medical cure for Ross River Virus [1]. Patients are treated with drugs to minimize inflammation and alleviate joint pain [1].

 

Rainfall & Mosquitoes

Heavy rainfall and high tides over the recent Australian summer have created the perfect environment for mosquito proliferation throughout Queensland [2]. The situation was exacerbated when Tropical Cyclone Marcia hit Queensland on February 20, 2015, resulting in widespread flooding [2,3]. These environmental factors contributed to an increased prevalence of mosquitoes, which led to an increased number of individuals being bitten by infected mosquitoes, ultimately resulting in this large outbreak of RRV. A major mosquito control program has been implemented by the Brisbane City Council to decrease the vector population in hopes of controlling the outbreak [2].

Australia is host to an assortment of mosquito breeds capable of spreading RRV [1]. To further complicate matters, each of these mosquito species has a preferred breeding habitat, making targeted vector control difficult. For example, the Aedes vigilax mosquito prefers to breed in salt marshes, while the Aedes normanensis mosquito proliferates in floodwater, and the Aedes notoscriptus is commonly found in backyards [1].

 

Prevention

Because there is no vaccine for RRV, prevention typically focuses on limiting contact with the disease’s vector – mosquitoes. This includes adding screens to your house and staying indoors during peak mosquito biting hours. If you are outdoors around sunrise or sunset, be sure to wear long-sleeved shirts, long pants, and use repellants containing DEET [1,2]. Reducing mosquito habitats and breeding sites is another important preventive measure. Any pool of water, including household items such as empty containers and flowerpots, can serve as a mosquito breeding ground.

There are also seasonal fluctuations related to the spread of RRV.  Water availability and temperature greatly impact mosquito prevalence. For instance, humid weather allows the mosquito to live longer allowing it to become infectious, breed, and infect a human. In the Northern Territory of Australia, for example, the main risk season is from December to March [1]. The highest risk is in January, when high tides and increased rainfall result in an increase of mosquitoes [1].

To address the outbreak in Australia, health authorities in Queensland recommend that residents clean out their gutters to limit stagnant water, as well as other mosquito breeding ground on their property [2]. Additionally, they have recommended that individuals add protective screens to their windows and doors, use repellents and sleep under insecticide treated nets [2].

 

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Sources:

  1. http://health.nt.gov.au/library/scripts/objectifyMedia.aspx?file=pdf/45/27.pdf&siteID=1&str_title=Ross%20River%20virus.pdf
  2. http://www.couriermail.com.au/news/queensland/queenslands-worst-ross-river-virus-outbreak-in-almost-20-years-hits-brisbane/story-fnn8dlfs-1227261900933
  3. http://news.yahoo.com/1-500-homes-damaged-cyclone-marcia-australia-060956262.html

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