Pathogen of the Month - 2019 Archive
January pathogen of the month:
Foot and Mouth Disease
What is it?
Foot-and-mouth disease (FMD) is a highly communicable viral disease caused by an Aphthovirus of the family Picornaviridae.
It primarily affects cloven-hooved animals of the order Artiodactyla. Livestock hosts include cattle, pigs, sheep, goats, and experimental infections in alpacas and llamas. FMD virus has also been reported in more than 70 species of wild artiodactyls, including bison, giraffes, Indian elephants, and several species of deer and antelope.
The disease is characterized by fever and vesicles in the mouth and on the muzzle, teats, and feet and is spread through direct contact or aerosolized virus via respiratory secretions, milk, semen, and ingestion of feed from infected animals.
In a susceptible population, morbidity reaches 100% with rare fatalities except in young animals. FMD was once distributed worldwide but has been eradicated in some regions, including North America and Western Europe. Outbreaks can severely disrupt livestock production and require significant resources to control, as in the 2001 UK outbreak.
History:
The first indications of FMD were recorded in 16th century Venice. The affected animals refused their feed, the oral mucosa showed redness and the animals had vesicles in the oral cavity and on their feet. Today it is considered one of the most important diseases of cloven-hoofed animals. The disease has been present in almost every part of the world where livestock are kept.
Mode of transmission:
Animals pick up the virus either by direct contact with an infected animal or by contact with foodstuffs or other things which have been contaminated by such an animal. They may also become infected by eating or coming into contact with some part of an infected carcass.
Are there preventative steps?
FMD is one of the most difficult animal infections to control. Because the disease occurs in many parts of the world, there is always a chance of its accidental introduction into an unaffected country.
FMD outbreaks are usually controlled by quarantines and movement restrictions, euthanasia of affected and in-contact animals, and cleansing and disinfection of affected premises, equipment and vehicles.
Rodents and other vectors may be killed to prevent them from mechanically disseminating the virus. Vaccination can be used to reduce the spread of FMD or protect specific animals. Vaccines are also used in endemic regions to protect animals from clinical disease. FMDV vaccines must closely match the serotype and strain of the infecting strain.
What is the current status?
In recent weeks, foot and mouth disease outbreaks have been reported in several areas of Asia. In India, The Department of Animal Husbandry, Veterinary and Dairy Development reported that 26 mithuns had died of foot and mouth disease in Papum Pare district since June. Officials said 2,957 animals had been either treated or vaccinated in the district.
A new outbreak was also reported among pigs in Hanoi's Ba Vi district. Local reports say 261 pigs belonging to 19 households in 6 communes of the district were affected by the disease. The Ministry of Agriculture and Rural Development's Department of Animal Health asked provincial authorities to kill the affected pigs. Local veterinary units initiated vaccinations of cattle in the area.
An outbreak was also recently confirmed in Israel involving a herd of recently vaccinated heifers.
What is CEEZAD doing?
CEEZAD is developing diagnostic and detection tools for FMD including a mutli-antigen print immunoassay test for expressed diagnostics of antibodies to FMDV. It is also developing an assay for detection of FMD virus at the site of infections (point of need, or PON, diagnostics).
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Sources: Merck Veterinary Manual, Biomed Central, The Cattle Site; CEEZAD
February and March pathogen of the month:
Chronic Wasting Disease
What is it? 
Chronic Wasting Disease is a prion disease of cervids (deer, elk, reindeer, moose). Prion diseases are a class of diseases caused by “prions,” which are infectious misfolded proteins that lead to neuro-degenerative changes in the brain. They are usually rapidly progressive and fatal.
CWD was first identified in captive deer in a research facility in the late 1960s in Fort Collins, Colorado and in wild deer in 1981.
By the 1990s, it had been reported in surrounding areas in northern Colorado and southern Wyoming. Once CWD is established in an area, there is a risk that it can remain for a long time in the environment. That means the affected areas are likely to continue to expand over time.
There have been no reports of CWD in humans. Animal studies suggest a potential for risk for non-human primates (such as monkeys); concerns have been raised about the potential for a risk to humans.
Mode of transmission.
Scientists believe CWD proteins (prions) likely spread between animals through body fluids like feces, saliva, blood, or urine, either through direct contact or indirectly through environmental contamination of soil, food or water.
Once introduced into an area or farm, the CWD protein is contagious within deer and elk populations and can spread rather quickly. According to the CDC, CWD prions can remain in the environment for years, so other animals can contract CWD from the environment even after an infected deer or elk has died or moved away.
What is the current status?
The Centers For Disease Control reports that Chronic Wasting Disease has been identified in either farmed or wild cervids in 24 states. That total includes 27 Kansas counties, most of them in the western part of the state but ranging eastward as far as Jewell County in the state’s north-central region. Officials of the Kansas Cervid Breeders Association note, however, that the actual instance of CWD in the state is low, equating to 1 in 200,000 deer.
Its impact in the U.S.
The greatest threat posed by CWD is to the nation’s hunting industry. In a 2006-2007 study, the CDC projected that nearly 20 percent of the U.S. population hunt for deer or elk from time to time, and more than two-thirds said they had eaten venison or other game meat. Since there is no confirmed evidence of the potential for the spread of CWD among humans, this data does not at the moment present a threat beyond that posed to the game industry itself.
The economic threat posed to the $4 billion hunting industry is a separate matter. Experts report that hunters nationwide are purchasing fewer deer licenses, a matter of concern both to states – which derive revenues from the sale of those licenses – and to the domestic cervid farming industry.
Its impact in Kansas
The Kansas Department of Wildlife, Parks and Tourism reports that the first case of CWD in deer was identified in 2001 in Harper County. A 2017 report put the total number of cases statewide at 142
Prevention/treatment
There is no cure for CWD and no method of vaccination or eradication. That means that the focus of health officials is on restraining the disease’s spread. This effort includes restricting the disease’s ability to move from farmed deer/elk populations – breeding farms and ranches – into wild populations and vice versa. This is accomplished by a program of CWD testing conducted at breeding farms. Industry officials are also working to identify genetically resistant animals in the same fashion the sheep industry did for Scrappie. Work also continues on gene editing techniques that might permit development of animals with immunity to CWD.
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Sources: DeerBusters.com, Kansas Department of Wildlife and Parks, CDC; North American Deer Farmers Association; CEEZAD
April pathogen of the month:
Canine Distemper
What is it?
The American Veterinary Medical Association describes canine distemper as a contagious and serious viral disease that attacks dogs’ respiratory, gastrointestinal and nervous systems. It can also be found in wildlife – foxes, wolves, coyotes and other canines. It also has been reported in various wild cats as well as seals.
The increasing ability of Canine Distemper to cross species, infecting cats and seals, is of intensified interest to researchers due to its implications for the potential uncontrolled spread of the virus, with high lethality rates for wild animals.
Mode of transmission
The most common method of spread of the disease is via direct airborne exposure – typically involving sneezing or coughing – from an infected dog or wild animal. However it can also be transmitted via infected food or water bowls. Though CDV outbreaks could occasionally pop up in animal shelters, the virus persists primarily in wildlife populations, particularly in the Northeast where canine cases of CDV are extremely rare. It circulates among numerous carnivore species, causing die-offs of raccoons, grey foxes, skunks, coyotes, wolves, and other animals.
History
Canine distemper has a long history, first having been diagnosed in Europe in the 18th Century. The first vaccine was developed in the 1920s. Still, canines remain at risk either because owners do not have their pets vaccinated or due to young pets’ proximity to infected wild animals, which have not been vaccinated. The disease is also an ongoing concern in animal shelters and pet stores, if there is an unvaccinated specimen.
How is the disease controlled?
In the United States, the most common and also the most effective means of control of the spread of the disease is via vaccination, usually to puppies to enable them to build up immunities. States generally require that vaccination occur when a puppy is six to eight weeks old with periodic booster shots.
Why is there concern now?
A recent outbreak of a new strain of canine distemper has raised concerns in North America. A young dog imported from South Korea into western Canada was later found to be infected with the Asia-1 strain of canine distemper virus (CDV), which until then had not been reported in North America.
Scientists at Cornell's Animal Health Diagnostic Center (AHDC) identified the virus in samples from the dog, which they suspect was part of a shipment of animals rescued from a Korean meat market by an animal welfare organization. About 2 weeks after the sick dog's arrival, it developed a cough and was lethargic. Ten days later, it developed muscle twitches, then seizures and ultimately was euthanized.
Dogs that are already immunized against CDV likely are not at risk from the Asian strain, but if the virus comes into contact with wildlife, it may take a serious toll on wild carnivore populations.
Can canine distemper be cured?
There is no cure for the disease, which is why veterinarians place such an emphasis as vaccination as a preventive tool. The disease is often fatal, and dogs that survive usually have permanent, irreparable nervous system damage.
What is Kansas State University doing?
The university’s College of Veterinary Medicine in 2018 prepared a video targeted at practicing veterinarians designed to acquaint them with the latest techniques for collecting nasal swabs to be used in the diagnostic process. A link to the video is https://www.youtube.com /watch?v=mhBL2XzQCeo&index=3&t=0s&list=PLNjV05pK4JEUCABbmIQhKyJzuwk3HbFwF
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Sources: avma.org, cdc.gov, Kansas State University College of Veterinary Medicine
May pathogen of the month:
Malaria
What is it? For centuries, malaria has been the most common zoonotic disease in the world. It is caused by a parasite infecting a mosquito that feeds on humans. When the mosquito bites a human host, the parasite is transferred to the host.
How widespread is malaria? The Centers for Disease Control reports that about 1,700 cases are diagnosed annually in the United States, most in travelers returning from areas where the disease is more common. Globally, the World Health Organization estimates that in the most recent year for which full data is available, 2016, about 216 million clinical cases were identified with about 445,000 fatalities, most of them African children. But the disease is also prevalent in South and Central America and the Caribbean, where 1 in 100 pregnant women are affected. Among all infectious diseases, only hepatitis B is more common.
What are the symptoms? The predominant symptom is fever; flu-like symptoms are also common. Nausea, vomiting and diarrhea are known to occur. Anemia and jaundice are also possible. Victims who do not receive prompt treatment can develop potentially fatal kidney failure or life-threatening seizures.
How is the disease controlled? Physicians last week began vaccinating children in the African nation of Malawi with the first effective vaccine against malaria. The vaccine is known as RTS,S, or Mosquirix. It was created by a British pharmaceutical group in 1987 and has since been under testing. Those expecting to travel to areas where malaria is known to be present can take preventive drug treatments before departing. Since the type of treatment can vary based on location, it is best to consult a physician. Beyond that, many of the classic preventive steps – notably mosquito netting and mosquito repellent – do provide some protection.
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Sources: Centers for Disease Control, World Health Organization, CEEZAD staff
June pathogen of the month:
Hantavirus
What is it?
Hantavirus Pulmonary Syndrome, known more simply as hantavirus, is a severe and potentially fatal respiratory disease in humans. It is carried by rodents, making it a potential threat even to those living in homes. Human-to-human transmission has not yet been reported in the United States, although rare cases of human-to-human transmission have been reported elsewhere.
How widespread is hantavirus? The Centers For Disease Control has been monitoring hantavirus infections since 1993; to date, more than 700 cases have been reported, 16 of them in Kansas. The virus appears to be more widespread in South America, with individual and small clusters of cases reported in nine nations on that continent. Large outbreaks are rare, but they can be serious. Scientists have listed the mortality rate from hantavirus at 38 per cent. In 2017 an outbreak in Washington state claimed three lives.
Hantavirus extends worldwide and shows different clinical presentations and severities. These presentations include HCPS and HFRS.It is most commonly found in rural areas with abundant forests, fields and farms for the rodent host.
How does the infection spread? In the United States, deer mice (along with cotton rats and rice rats in the southwest and the white-footed mouse in the northeast) are common hantavirus reservoirs.Humans are most at risk when they engage in activities with the potential to put them in contact with rodent urine, droppings, saliva or nesting materials. This can include sweeping and dusting.
When fresh rodent urine, droppings or nesting materials are stirred up, tiny droplets containing the virus get into the air. This profess of infection is known as “airborne transmission.” Opening or cleaning cabins, outbuildings and other structures closed for the winter can also present concerns. Campers and hikers can also be exposed.
The good news is that hantavirus cannot be transmitted by human-to-human contact. In other words, you cannot be infected by touching an infected person.
What are the symptoms? Hantavirus symptoms include fatigue, fever and muscle pains, particularly in the large muscle groups. These can be accompanied by headaches, dizziness, chills and abdominal pain, nausea, vomiting, and diarrhea.
Are there treatments or vaccines? According to the Canadian Centre for Occupational Health and Safety, there is no specific vaccine, treatment or cure for hantavirus infection. However, early recognition and intensive medical care can help with recovery. Infected people may be given medication for fever and pain.
Are there current outbreaks? During May of 2019, several hantavirus outbreaks have been reported, including in the United States. Health Department officials in Colorado reported the year’s first case earlier this month, although few details were provided. The New Mexico Department of Health also reported a case involving a woman from McKinley County near Gallup in the northwestern part of the state. That victim was reported to be resting at home following hospitalization. In San Diego County, California, a deer mouse tested positive for the disease, although no human cases were reported.
The most serious current outbreak is in Germany, where an outbreak is considered widespread. The situation is especially prevalent around Stuttgart, with more than 200 registered cases in Baden-Wurttemberg state this year alone.
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Sources: Centers for Disease Control, CEEZAD staff
August pathogen of the month:
West Nile Virus
W
hat is it and how widespread is it? West Nile virus is the most common mosquito-borne disease in Kansas and the United States. Several species of mosquitoes are responsible for transmission of arboviruses, but Culex species are the primary vector for West Nile virus in the United States.
What is its history? The World Health Organization says that West Nile Virus was first isolated in a woman in the West Nile district of Uganda in 1937. It was identified in birds in the Nile delta region in 1953. Human infections attributable to WNV have been reported in many countries around the world for over 50 years.
In 1999 a West Nile Virus strain circulating in Israel and Tunisia was imported in New York, producing a large and dramatic outbreak that spread throughout the USA in the following years. The outbreak highlighted that importation and establishment of vector-borne pathogens outside their current habitat represent a serious danger to the world.
H
ow does the infection spread? The Centers for Disease Control says mosquitoes become infected when they feed on infected birds. Infected mosquitoes then spread West Nile virus to people and other animals by biting them with horses being the most susceptible. In a very small number of cases, West Nile virus has been spread through such means as exposure in a laboratory setting, blood transfusion or organ donation.
What are the symptoms? Most people do not develop symptoms. Only about 1 in 5 infected persons do develop symptoms, generally a fever
(red indicates high level of risk; yellow indicates moderate level of risk.)
accompanied by headaches, body aches, joint pains, vomiting, diarrhea or rash. While people usually recover quickly, it is possible for fatigue to last for weeks or even months.
Are there treatments or vaccines? There is no vaccine to prevent West Nile Virus in humans. There are approved vaccines for use in horses. The CDC recommends use of over-the-counter pain relievers to reduce fever or relieve other symptoms. In severe cases, hospitalization may be necessary.
Are there current outbreaks? The Kansas Department has identified about 70 Kansas counties – essentially the eastern two-thirds of the state – as at high risk for West Nile Virus. That is largely due to this summer’s heavy rains, which have increased the number of breeding areas for mosquitoes. That is coupled by normal rising summer temperatures, which shortens the time required for mosquitoes to mature to biting adults. It should be noted, however, that as of mid-July no confirmed cases of West Nile Virus had been reported.
Sources: Centers for Disease Control, CEEZAD staff