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OUTLINE For Podcast 14 mar 2010

 Update on Wildlife Diseases

by

Jerry Genesio

His Blog http://naturalunseenhazards.wordpress.com/

1. I.      Rabies:

A.  Good News

1. 1.    The rabies vaccine and rabies immune globulin shortages appear to be over.   

1. a.    Rabies immune globulin shortage was caused by Talecris –  an international company with facilities in the US, Canada, and Europe  – when it decided to prepackage RIG in a ready-to-use syringe.  There were two problems:  the dose was too strong for infants, and the needle gauge was too big for infants.  The company had to completely retool leaving only one other company to supply the needs of the entire world. 
2. b.    Rabies vaccine shortage was caused by Sanofi Pasteur of France when it decided to update and modernize one of its manufacturing plants which caused a production shutdown.

1. 2.      There may be a new rabies virus vaccine in the not too distant future.  According to new research at the Jefferson Vaccine Center in Philadelphia, PA, and published in the Journal of Infectious Diseases, a single inoculation may, one day, be all it takes for rabies vaccination.  Presently, the standard vaccine is made from inactivated rabies virus, whereas the experimental vaccine is made from a live rabies virus that is modified by removing the M gene, thus inhibiting its spread within the vaccine recipient.  The alternative may be to treat people pre-exposure, as they are with many of the current vaccines used.  Although the vaccine was tested primarily to be a post-exposure vaccine, the data collected shows it would be effective as a pre-exposure vaccine as well. The new vaccine is still a long way from being submitted to the Federal Drug Administration for approval, and the fact that it is made from a live form of the rabies virus likely means much additional time will have to be added to the process in the interest of safety, but it’s a promising start.  The research that remains to be done will be very expensive, but anything that may prevent tens of thousands of rabies deaths each year, truly horrible deaths, is well worth the cost.

B.  The Bad News

1. 1.     There haven’t been any cases of human rabies reported to the CDC yet this year, but there were 4 human cases reported last year – that’s the highest number in the past 5 years.

1. The urban wildlife population is increasing by leaps and bounds and the numbers are unprecedented, particularly with regard to raccoons, skunks, foxes, coyotes, bats, and perhaps above all, feral cats, which in and of itself has gotten totally out of hand.  I think it’s fair to say a national dialogue is beginning concerning feral cats and whether Trap, Neuter, Release (TNR) programs work or in fact exacerbate the problem.  Some say Trap and Euthanize is the only solution.

C.  The Really Ugly News

1. 1.    A new strain of a northern Arizona rabies virus has mutated among skunks and foxes, and experts believe it is evolving faster than any other new rabies virus on record. Animals infected with the rabies virus all too often attack people, and both skunks and foxes have tested positive for a contagious strain of rabies virus usually associated with big brown bats. Normally, however, skunks and foxes have not been able to pass the virus on to their kin short of biting, licking, or scratching them. It appears that this particular strain of the virus has bridged that limitation and it is being passed on simply through social contact, as the influenza virus moves among human social groups.  Could the virus mutate further and become contagious in humans? A molecular virologist at Emory University School of Medicine in Atlanta believes this should be a major concern. 

1.  Other Viral and Bacterial Diseases (Clearly, the CDC, NIH, and researchers recognize that tick and mosquito borne diseases are becoming an increasingly significant threat here in the U.S. because they are funding some very ambitious studies to combat these diseases.  Lyme disease may be the bombshell that woke them up.)

A.   Good News

1.  Researchers from the La Jolla Institute for Allergy & Immunology are working on vaccines to fight several of the world’s most dangerous infectious diseases – tuberculosis, malaria, and dengue virus.  The initial phase of this project has begun with a five-year, $18.8 million federally-funded set of projects.

1.  Hawaii Biotech Inc., a privately held biotechnology company has conducted its first human clinical trials with a West Nile virus vaccine, which will be followed by a dengue virus vaccine candidate.  Hawaii Biotech, founded in 1982, is currently in Phase 1 clinical studies with a dengue vaccine candidate, and is in pre-clinical development with a vaccine for tick-borne encephalitis. Hawaii Biotech is also working on vaccine candidates for malaria and influenza.

1. 3.     Purdue University is leading a team of researchers in a federally funded effort aimed ultimately at developing better vaccines and antiviral drugs against two types of disease-causing viruses. One group, called flaviviruses, includes West Nile and dengue. The other group, called alphaviruses, includes eastern equine encephalitis and chikungunya. (For more information on chikungunya, see the Natural Unseen Hazards Blog post for September 23, 2009.)

1. 4.     A team of researchers from several institutes teamed up recently to develop a broad-spectrum antiviral compound, dubbed LJ001, capable of stopping several viruses including: Ebola, HIV, Hepatitis C, West Nile virus, Rift Valley fever and yellow fever.  The team included scientists from the University of Texas, UCLA, Harvard University, the U.S. Army Medical Research Institute of Infectious Diseases and Cornell University.  If this compound has the same effects in humans as it did in mice, then it will revolutionize the way we treat viruses and greatly expand the lifespan of individuals. Vaccinations, a preemptive approach to many viral infections, would be a thing of the past and LJ001 could be prescribed to fight viral infections just and commonly as antibiotics are prescribed to fight bacterial infections.                                                                                                 

(Rift Valley fever is a fever-causing viral disease that affects livestock and humans in Africa. It is most common during years of heavy rainfall.  People get Rift Valley fever mainly from the bite of an infected mosquito. The disease can also be spread by contact with the blood or body fluids of an infected animal. It could eventually be introduced to the U.S. naturally, or as a tool of terrorism.)

1. 5.     No vaccine currently exists for West Nile Virus, but a new therapeutic made from tobacco plants has been shown to arrest the infection, according to a new study.  Elderly individuals and those with depressed immunity are particularly vulnerable to West Nile, a mosquito-borne illness that can cause potentially lethal inflammation of the brain.  The study, conducted by Arizona State University scientists, is the first to demonstrate a plant-derived treatment to successfully combat West Nile Virus after exposure and infection.

B.    Bad News

1. The CDC cautions that Dengue Fever is an emerging threat in the continental United States.  Dengue (den-gee) also (DENG-gay) is a disease that is endemic in most of the world including at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean.  The World Health Organization (WHO) estimates that 50 to 100 million infections occur yearly, including 500,000 of the more severe dengue hemorraghic fever (DHF) cases and 22,000 deaths, mostly among children.

1. Origin:  The four dengue viruses (not surprisingly called Dengue 1, 2, 3, and 4) originated in monkeys and independently jumped to humans in Africa or Southeast Asia between 100 and 800 years ago.  Dengue remained a relatively minor, geographically restricted disease until the middle of the 20th century.  The disruption of the second world war – in particular the coincidental transport of Aedes mosquitoes around the world in cargo –  are thought to have played a crucial role in the dissemination of the viruses.  Dengue hemorraghic fever was first documented only in the 1950s during epidemics in the Philippines and Thailand.  In 1981 large numbers of Dengue hemorraghic fever cases began to appear in the Carribean and Latin America.  Most dengue cases in U.S. citizens occur in Puerto Rico, the U.S. Virgin Islands, Samoa and Guam, which are endemic for the virus.  Dengue and DHF have been a particular challenge in Puerto Rico where outbreaks have been reported since 1915 and large island-wide epidemics have been documented since the late 1960s. The most recent island-wide epidemic occurred in 2007, when more than 10,000 cases were diagnosed. In 1934, there was an outbreak of dengue in Florida and 25,000 people fell ill with the disease.  Now, more than 75 years later, 20 new cases were confirmed in Key West, Florida, last year.

1.  Symptoms:  The principal symptoms of dengue fever (DF) are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising).

Dengue hemorrhagic fever (DHF) is characterized by a fever that lasts from 2 to 7 days, with general signs and symptoms consistent with dengue fever. When the fever declines, symptoms including persistent vomiting, severe abdominal pain, and difficulty breathing, may develop. This marks the beginning of a 24- to 48-hour period when the smallest blood vessels (capillaries) become excessively permeable (“leaky”), allowing the fluid component to escape from the blood vessels into the peritoneum and pleural cavity. This may lead to failure of the circulatory system and shock, followed by death, if circulatory failure is not corrected. In addition, the patient with DHF has a low platelet count and hemorrhagic manifestations, tendency to bruise easily or other types of skin hemorrhages, bleeding nose or gums, and possibly internal bleeding.

1.  Transmission:  Dengue is transmitted between people by Aedes mosquitoes, which are found throughout the world.

1. Incubation:  Symptoms of infection usually begin 4 – 7 days after the mosquito bite and typically last 3 – 10 days.

1. Treatment:  There is no specific medication for treatment of a dengue infection. Persons who think they have dengue should use analgesics with acetaminophen (Tylenol) and avoid those containing aspirin. They should also consult a physician. If they develop vomiting and severe abdominal pain in the first 24 hours after the fever declines, they should go immediately to the hospital for evaluation.

1. Prevention:  There is no vaccine for preventing dengue. The best preventive measure is to use mosquito repellents containing 20% to 30% DEET as the active ingredient on exposed skin and clothing to decrease the risk of being bitten by mosquitoes.

1. According to Dr. James Diaz, of the Louisiana State University Health Sciences Center in New Orleans, LA, “Chikungunya is coming,” and “(w)e’re very worried”.

1.  Origin:  Chikungunya is the name of a viral disease that was first isolated from the blood of an infected patient in Tanzania in 1953. 

1. Transmission:  The Chikungunya virus is mosquito-borne and can be transmitted to humans by the bite of an infected Aedes mosquito.

1. Cycle:  The mosquitoes become infected when feeding on the blood of infected humans and then spread the virus to other humans.  Monkeys and other primates, and possibly other wild animals, may also serve as reservoirs.

1.  Symptoms:  “Silent” (asymptomatic) Chikungunya virus infections do occur, but it’s not yet known how commonly this happens.  Typically, symptoms include fever, headache, fatigue, nausea, vomiting, muscle pain, rash, and joint pain. Some patients experience incapacitating joint pain, or arthritis, which may last for weeks or months. The disease can be fatal, but most deaths are associated with older patients. While 90% of West Nile Virus infections are asymptomatic, the overwhelming majority of those infected with the Chikungunya virus are quite sick.

1. Incubation:  Onset of symptoms occurs from 2 to 12 days following infection, but usually 3 to 7 days.

1. Treatment:  There is no vaccine or specific antiviral treatment currently available for Chikungunya Fever. Treatment to relieve the discomfort of fever and aching can include rest, fluids, and pain relievers such as ibuprofen, naproxen, or acetaminophen. Aspirin should be avoided.

1. Immunity:  Chikungunya virus infection (whether clinically apparent or silent) is thought to confer life-long immunity.

1. Geographic Range:  After its isolation in 1953, Chikungunya virus was identified as the cause of human epidemics in many areas of Africa and Asia.  Since 2005, the disease has caused outbreaks and fatalities in India and the French island of Réunion.  As of May 2009, the virus has been spreading throughout many parts of Thailand, especially among Thai military troops. It has also reached Italy and France. The worldwide distribution of Aedes mosquitoes, and ongoing Chikungunya virus epidemics, signal that the risk of importation into new areas by infected travelers is likely. The virus is hyper-endemic in the islands of the Indian Ocean, and air travel will import infected mosquitoes and humans.

1. According to a Colorado State University study, pumas and bobcats host the fleas that cause the plague.

1. Yersinia pestis is a flea-borne bacterium that causes plague, which is maintained among rodent hosts and their fleas, but spillover into populations of predators that feed on rodents can result in the geographic spread of the disease.  Domestic and feral cats are a major source of human plague infections in the United States, putting veterinary workers and pet owners at risk.  Twelve cases of plague transmission from wild animals to humans have been documented, including a fatal case of human pneumonic plague in 2007 that resulted from direct contact with an infected puma.  It seems only reasonable   that coyotes and wolves might also host fleas that carry the plague because they also feed on rodents.  Recommendations include wearing disposable gloves, long pants, and long-sleeved shirts when handling anesthetized animals and using an N95-rated mask when conducting necropsies or handling deceased animals. Outside of human infections, plague could constitute a problem for field conservation in areas of high plague activity.  Wildlife professionals are always at risk, especially when dealing with rodent predators, and your customers should give this serious consideration before complaining about what you might charge.

C.   The Really Ugly News

1.  The Food and Drug Administration (FDA) held a public workshop last year entitled “Emerging Arboviruses: Risk Assessment for Blood, Cell, Tissue and Organ Safety.”  The purpose of the workshop was to assess the risk and discuss approaches to minimize the incidence of transmission of arboviruses via transfusion, infusion, implantation or transplantation in the United States.  Arboviruses are a large group of viruses that are spread by certain invertebrate animals, most commonly blood-sucking insects. Arboviruses such as Dengue virus, Japanese Encephalitis virus (JE), tick-borne encephalitis virus (TBE) and West Nile virus (WNV) are becoming increasingly widespread.  Transmission of WNV and Dengue virus through blood transfusion has been well documented.  Transfusion transmission of the Colorado tick fever (CTF) virus, a tick-borne agent present in the U.S., also has been reported.

1. In a recent study published in the journal Transfusion, researchers at hospitals in Rhode Island have seen a dramatic increase in Transfusion-Transmitted Babesiosis (TTB) cases.  The researchers studied Babesiosis infections reported to the Rhode Island Department of Health between 1999 and 2007 and found 346 cases of which 21 appeared to have been transmitted via blood transfusion rather than the known vector of the parasite, the Deer tick.  This translated to one case in every 15,000 units of blood transfused.  In February 2009, the New York City Health Department issued a health advisory following the discovery of seven cases of the parasitic disease transmitted via blood transfusion in the previous six months.  Babesiosis is caused by microscopic parasites that infect red blood cells and are spread by Deer ticks. In the United States, tick borne transmission is most common in parts of the Northeast and upper Midwest; and it usually peaks during the warmest months. 

1. Author’s note:  I was told long ago – if you don’t need a blood transfusion to save your life, you don’t need a blood transfusion.

Jerry Genesio is the author of “Unseen Hazards That Threaten Hunters, Campers, and Hikers: What you should know about pathogens commonly found in wildlife.”  He is a University of Southern Maine graduate and served six years in the U.S. Marine Corps (1956-62).  Jerry was employed for nearly 20 years (1970-88) by Cutter Laboratories as a blood specialist in Cutter’s Biological Products (Human) Division.  From 1988-93 he worked with United Nations NGO’s providing humanitarian aid to children in war torn areas of Central America, and from 1994-96 worked with the Children of War Rescue Project evacuating war-wounded children from Bosnia.  He is now retired and spends much of his time researching and writing articles and books focusing on U.S. and Natural History. Jerry is a native of Massachusetts and lives in Bridgton, ME, and Wilmington, NC, with his wife, Judy.

Jerry Genesio