Dr Kristine Smith of the EcoHealth Alliance has led a team investigating the horrifying possibilities associated with wildlife imports. Illegal wildlife products include live rats, chimpanzees and monkeys (often called bushmeat), but meat from these creatures is also imported. At risk of infecting humans are the RNA viruses, herpes viruses, retroviruses and many other potential health problems. A zoonosis is a disease transmitted from animals to ourselves. Most (75%) of recent new infections in humans are zoonoses. Unless US laws are strictly enforced, the country might as well be suffering new infections at a similar rate to these animals' host countries.
In southwest China, SARS quickly established itself and spread to 29 other countries in a couple of months, involving 774 deaths and 8098 cases. A palm civet cat is eaten in the restaurants of Guangdong, and the infection was traced to restaurant workers who had bought, butchered and cooked these animals. The respiratory and gastrointestinal disease is an RNA virus. Flu, hepatitis C and polio. give you an idea of the extent and capability of RNA virus as a successful disease organism. Among the biggest consumers of imported wildlife and wildlife products is the USA. 120,000 wild live animals are legally imported into the US every year along with 25 million kg of non-live wildlife! New York imports the most, along with LA and Miami. Deemed illegal are some Chinese, Filippino, Hong Kong, Thai and Nigerian creatures. One good reason for excluding them is their endemic pathogenic viruses (H5N1 'flu, Nipah virus and simian (primate) retroviruses for example).
There is minimal surveillance in these areas and no surveillance at all for wildlife products. So you could say the illegal catches above were just lucky. Not so lucky are the animals and human victims of Amphibian chytridiomycosis (see Earth Times), exotic Newcastle's disease and monkeypox, all of which have "invaded" the US recently. The monkeypox outbreak was down to a single imported batch of infected monkeys. The only restrictions are on certain turtles, bats, civets and African rodents, while USDA regulates a few birds, fish, tortoise, hedgehogs, various exotic ruminants, tenrecs and brushtail possums because they cause agricultural health problems.
African wild creatures defined as bushmeat have often created disease "emergence." Usually, it's a retrovirus involved, having produced at least three diseases originating in primates. Via European airports, the little understood routes for smugglers can include the 273 tons imported into Paris every year.
For the purposes of this study, five airports were used. At JKK, in Queens, New York, and four other airports, studies gathered illegally-imported shipments, but didn't quantify the rate of the importation. Only a few pieces of data were logged, photographs were taken and ID of species was carried out if possible. Then the pathogen count began, with special searches for leptospira and anthrax, herpesviruses, filoviruses, paramyxoviruses, coronaviruses, flaviviruses, orthopoxviruses, and simian retroviruses (SIV, STLV, SFV). From 28 usable confiscations, with material from 44 species, simian foamy virus and herpes viruses were readily detected. Two genera of herpes viruses included cytomegaloviruses and lymphocryptoviruses and interestingly, multiple viruses were found in some mangabey monkeys (Cercocebus)and baboons.
Zoonoses are little understood by the general public, except perhaps that we can catch infections readily from more closely related species and less readily form distant relatives (eg. bird 'flu). This attempt at qualitative surveillance on a limited number of pathogenic organisms should obviously be followed up with regular quantitative studies. This would establish just how much risk is being taken. But it is a large risk. In addition, of course, endangered animals are involved, and other countries have found dangerous excesses when investigating bushmeat imports (in France). One major danger for the near future is the increasing pathogenicity of a virus, once established in human tissues. A virus may be incapable of transmission to another human, but that virus can soon mutate into a functioning transmissible disease., causing epidemics. Following our pig and bird virus events, you would like to believe that we are ready for a worse "hit" from a closer relative. That remains to be seen.
Latent infections are common in retroviruses and herpesviruses, although severe disease such as catarrhal fever and herpes B has been caused in non-host species such as humans. A virus can lie dormant like the Epstein-Barr virus (EBV) in 90% of the American adult population. Antibodies in the blood prove it has been present in that number of people. Then add on the viruses that now appear on our doorstep, ready to increase the number of apparently symptom free infections. Now we have to consider all of those horse, carnivore, reptile, bird and other diseases which this research was unable to cover. Perhaps the word time-bomb will make government take action and govern where it surely must.