Coughs and sneezes, bats, birds, pigs and you
By Jack Woodall, PhD
Posted on One Health Initiative website December 14, 2012
In 1998, pig farmers in northern Peninsular Malaysia noticed that their pigs were getting a disease that caused loud coughing. Next, people started coming down with fatal encephalitis, which was attributed to endemic, mosquito-transmitted Japanese encephalitis. But some of the victims also had atypical pneumonia, some of them had been vaccinated against Japanese encephalitis and would have been immune to it, and all of them were ethnic Chinese. The solution to the riddle was that in Moslem Malaysia, only non-Moslem Chinese raised pigs, and the vaccination did not protect because it was a different virus, a new member of the paramyxovirus family that is responsible for respiratory disease in humans and animals. It was named Nipah virus, after the Malaysian village from which the specimen came which yielded the first isolate of the virus. Its origin was traced back to fruit bats, which had been displaced from their original habitat by forest clearing and sought alternate food on farms. They were feeding on mangoes in trees overhanging the pig pens, into which their dejecta fell and contaminated the pig feed and water.
Cases turned up in later years, also in Asia: in Bangladesh between 2001 and 2008, outbreaks claimed over 129 victims with a case fatality rate (CFR), of about 75%; and in 2007 in India, with more than 70 cases and a 70% CFR. Transmission was no longer airborne from livestock, but was still connected with fruit bats. In those countries, collectors of palm sap for fermenting into palm wine found that their containers were attracting the bats, which were contaminating them in the same way as in Malaysia. By keeping out the bats with slatted bamboo mats over the cups on the palm trees, these outbreaks were curtailed.
Type A influenza viruses, including H3N2 and its variants, commonly cause outbreaks in pig farms. Most of the type A influenza viruses that infect swine are genetically very different from human (seasonal) influenza viruses. In 2012 an influenza A(H3N2)v (v for variant) swine influenza virus strain has been causing human infections at agricultural fairs in some parts of the United States. It has not so far been detected in pigs in European countries. Only people in direct contact with infected swine, such as in barns and livestock exhibits housing swine at fairs, are likely to be at risk of contracting this H3N2v strain of influenza virus. However transmission of this variant strain is thought to occur in the same way that seasonal flu transmits in people, which is mainly through coughing or sneezing by people who are infected. People also may become infected by touching something with flu viruses on it and then touching their mouth or nose. In most cases, variant flu viruses have not spread widely from person to person. ....
To find out Dr. Woodall’s One Health prescription for “What we can do” to help protect ourselves from Japanese encephalitis, Swine flu, Severe Acute Respiratory Syndrome (SARS), Bird flu, Novel coronavirus and others, please read this entire timely article by clicking on:
Dr. Jack Woodall is a member of the One Health Initiative Autonomous pro bono Team: Laura H. Kahn, MD, MPH, MPP ▪ Bruce Kaplan, DVM ▪ Thomas P. Monath, MD ▪ Jack Woodall, PhD ▪ Lisa A. Conti, DVM, MPH. He is a Co-founder and Associate Editor of ProMED-mail and contents manager of the One Health Initiative website’s ProMED Outbreak Reports page http://www.onehealthinitiative.com/promed.php.
Provided to the One Health Initiative website December 6, 2012.