Sunday 25 March 2018

Rabies outbreak kills at least five in South Africa.

An outbreak of Rabies has killed at least five people in South Africa since December 2017, with two more deaths thought likely to have been caused by the disease. The confirmed cases of the disease occurred in Limpopo, Mpumalanga, Eastern Cape and KwaZulu-Natal provinces, with two further possible cases in Free State and Eastern Cape provinces, where it was not possible to obtain tissue samples for testing. Rabies can in theory be caught from the bite of any infected Mammal, but almost all cases in Humans are caused by Dog bites. Of the recent South African cases all are thought to have been transmitted following attacks by infected Dogs, with the exception of the Free State infection, where the patient was bitten by a Cat. Most provinces of South Africa are usually considered to be free of the disease, but it is endemic to wild Dog populations in KwaZulu Natal and Eastern Cape Provinces, with the infection sometimes spreading to domestic animals, which can in turn be transported to other parts of the country. South Africa aims to be completely free of Rabies by 2030, and the vaccination of all domestic Dogs and Cats in the country is, at least in theory, compulsory.

A pet Dog being vaccinated against Rabies in Soweto, South Africa, following an outbreak of Rabies in 2010 which prompted the introduction of compulsory vaccinations against the disease across the country. Daniel Born/Gallo Images/Times.

Rabies is caused by Viruses of the genus Lyssavirus, a member of the Rhabdoviridae Family of negative-sense single-stranded RNA Viruses, which also includes pathogens attacking Fish, Insects and Plants. Rabies is spread through the saliva of infected animals, and causes hydrophobia (fear of water),  anxiety, insomnia, confusion, agitation, abnormal behaviour, paranoia, terror, and hallucinations, followed by paralysis, coma and death in Humans. Many animals (notably Dogs) become extremely aggressive at this stage and will bite anything that comes near them, helping to spread the disease. In Humans, the disease typically has a gestation period of about three months, during which time the disease can be treated by repeated vaccination and doses of human rabies immunoglobulin, though if treatment is not begun within ten days of infection it is less likely to be successful, and once the patient starts to develop symptoms the disease is almost invariably fatal. Any wound thought to have been caused by an infected animal should be washed thoroughly under running water for at least five minutes, before being treated with alcohol or iodine, and immediate medical attention sought.

Transmission electron microscope image with numerous rabies virions (small, dark grey, rodlike particles) and Negri bodies (the larger pathognomonic cellular inclusions of rabies infection). Centers for Disease Control and Prevention/Wikimedia Commons.

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