| MicrobiologyBytes: Virology: Bushmeat | Updated: June 6, 2005 | Search |
| Reduction of bushmeat consumption or even prohibition of bushmeat is probably impossible due to the poor socio-economic situation in many of the countries where bushmeat is eaten and due to the lack of measures to provide alternatives. I have also shown that it is the bacterial, viral and prion zoonoses acquired from bushmeat and exotic pets that could endanger life on an apocalyptic scale if the various types of prophylactic, antibiotic and anti-viral treatments were not available. Before medical interventions, severe reduction of the human race from the infection of a deadly disease "from 1345 to 1360 the black death caused the death of 24 million people just in Europe, at the time this was a quarter of the world's population (Fritz et al. 1996)." But with today's prophylactic and postexposure therapies and processes such as ring vaccination and isolation and containment of diseases via boarder control and barrier nursing, we can prevent the spread of potentially deadly zoonoses such as plague, rabies and SARS. For a disease to end the human race it must have the ability to prevent humans from reproducing either via killing all humans or by killing offspring and therefore preventing them from reaching a reproductive age and hence reproducing. |
A number of problems could cost humans dearly, for example the lack of prophylaxis and treatment for Ebola virus (EBOV). Due to its high fatality rate and the symptoms that the disease manifests EBOV is one of the world's most feared diseases. Ebola has been acquired from the consumption of a number of different species of NHPs infected with EBOV. The bushmeat trade is a multi-million dollar industry and a vast amount of bushmeat that was still entering the UK. Hypothetically there is a possibility that EBOV could enter the UK and not only infect the person who transported the bushmeat but the wholesaler and the people who prepared and consumed the meat. Each one of these people from the original contamination chain could infect others and the spread of the disease would radiate outwards and in a densely populated region the effects could be devastating especially with no known cure.
During the SARS outbreak in 2003 a doctor from the Guangdong Province stayed in the Metropole Hotel in Hong Kong, during his stay he infected 14 guests on the same floor who in turn disseminated the disease (from China) to Hong Kong, Canada, Singapore and Vietnam (WHO SARS Transmission 2003). A similar incident could hypothetically occur with a person infected with EBOV because from the time of contact with the index patient or bushmeat, the newly infected person could fly to any country in the world in roughly 24 hours this would be within the average EBOV incubation time of 2-12 days. The outcome would be a number of EBOV epidemics worldwide which if not dealt with quickly and efficiently could lead to thousands of fatalities. But it would not end the human race because the most devastating strain can only cause 90% fatalities.
Recently there has been an outbreak of Marburg haemorrhagic fever in Angola. To date (08.04.05) there have been 205 cases with 180 deaths with the majority of the cases originate from the Uige Province. WHO reported that its mobile surveillance teams have been driven out of the area by local people, who are now extremely fearful of the disease due to its high fatality rate and the inability to cure infected individuals. WHO at present are being prevented from isolating infected patients and burying bodies of the deceased safely, this will probably lead to an increase in the number of cases of Marburg. It is also possible that the scenario above whereby SARS was disseminated globally could also occur with Marburg Haemorrhagic Fever (WHO Disease Outbreak News Marburg Virus Update 9 2005).
Above I have discussed a hypothetical scenario whereby thousands of people could die from EBOV or Marburg and earlier I disregarded the possibility of a known bacterial zoonosis ending the human race. Now due to the low levels of disease manifestation (if any SFV) and the presence of preexposure prophylaxis, PEP, drug treatments and the less than 100% probability of fatalities I would also disregard the possibility of MPV, Rabies, SARS, SFV and HTLV of ending the human race. I will also discard the possibility of prion diseases in ending the human race because one can only contract the disease from eating prion infected tissues. One also needs to have a genetic susceptibility to the prion diseases to contract them. Therefore it is unlikely that CWD will end the human race.
In 2000 WHO produced new healthy life expectancy figures using Disability Adjusted Life Expectancy (DALE), DALE took into account that people in poorer countries were extremely susceptible to infectious diseases and that disease meant that people did not live all of their lives in perfect health. Therefore the average time for life in disability (in individual countries) was subtracted from the overall life expectancy to produce DALEs. It was found that the bottom 10 ranked countries all had major epidemics of HIV, which had severely reduced life expectancy (only for babies born in 1999) examples of these countries and their DALEs include Sierra Leona with 25.9 years Zambia with 30.3 years and Ethiopia with 33.5 years. According to WHO HIV/AIDS is the leading cause of death in some Sub-Saharan countries and has reduced healthy life expectancy dramatically by 5-10 years (WHO Healthy Life Expectancy Rankings 2000). In 2004 HIV was the cause of 3.1 million deaths globally and there are 39.4 million people infected with HIV. Also thousands of people are carrying HIV without any knowledge and are unwittingly infecting more people. Therefore this pandemic is having an increasingly devastating effect on the global population. But could it end the human race?
There is no licensed preexposure prophylaxis (for HIV) and the drugs used to treat patients only delays the onset of AIDS, death is inevitable. But due to the slow progression of the disease humans are still able to reproduce therefore the human race can continue. Importantly not all infants of HIV infected mothers are carriers of HIV, according to WHO's Mother-to-child transmission (MTCT) of HIV website 15-30% of HIV infected women will transmit HIV during pregnancy and child birth whilst a further 10-20% will infect their infants via breastfeeding if precautions such as antiretroviral treatment are not used. Therefore children of HIV infected patients have less than 50% chance of contracting HIV. I believe that HIV will not end the human race because there are countries which have a good standard of sexual education and therefore people will take precautions such as using condoms to prevent HIV acquisition. Also as discussed above not all HIV infected mothers transmit HIV to their children, hopefully these children can learn from the mistakes of their parents and be more cautious with sexual partners and used precautions, condoms.
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Man's weakness for unprotected, promiscuous sexual intercourse will mean that unless a vaccine or effective drug treatment is discovered HIV will continue to spread within society leading to millions of deaths. HIV fatalities will not be the only cause of death in societies affected by HIV, orphans of HIV deceased parents are suffering due to a lack of basic essentials, food and water especially in third world countries. Also HIV tends to effect the sexually active population this is also the section of society that works to maintain the normal everyday running of a country. With a reduction in this section of the population there will be a decline in socio-economic prosperity, poverty will prevail and thousands will die. Therefore diseases acquired and derived from bushmeat will probably not end the human race, but they may threaten to severely reduce the global population in the not so distant future.
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