The National Institute for Communicable Diseases (NICD) says it is taking measures to prevent the outbreak of bubonic plague in humans after a rat, found in an informal settlement in Mayibuye in Tembisa, tested positive for plague antibodies on 16 March.
The NICD, together with environmental health services, made the plague discovery after collecting samples for a monitoring programme that tests for various rodent-borne diseases including plague. Thirteen rats were collected from the informal settlement, and one of them tested positive for plague antibodies.
Garbage is still going uncollected in Johannesburg. Nearly 4,000 Pikitup workers have been on strike, demanding a R10,000 a month basic salary and the removal of Pikitup head Amanda Nair. The unprotected strike began five weeks ago and has continued through several rounds of failed negotiation between Pikitup management, the City of Johannesburg and the South African Municipal Workers Union (Samwu).
According to John Frean, Associate Professor at the Centre for Opportunistic, Tropical and Hospital Infections at the NICD, the discovery is reason to intensify monitoring and control to prevent the disease occurring in humans: "Flea control to protect the community and intensified surveillance to detect further evidence of plague activity, have been instituted. The finding is an early indication that escalation of surveillance and control activities... are required."
Don't handle live or dead rodents
Frean emphasised that there is "no evidence of current infection, only of previous exposure" in the infected rat. He said "...the absence of unusual rodent mortality suggests that there is no outbreak of rodent plague in progress at present, and there is no immediate threat to human health." According to the World Health Organisation, plague is caused by the bacteria Yersinia Pestis. It is usually spread between rats by bites and by fleas. It is also usually spread to humans by fleas carrying the bacteria from rats.
Read: Rodent control
In the 14th century it was known as the Black Death in Europe and killed tens of millions of people. If left untreated, 30% to 60% of people with it die. According to the US Centres for Disease Control, about 1,000 to 2,000 cases worldwide are reported to the World Health Organisation annually, though it is believed the real number of cases is much higher. The last outbreak of bubonic plague in South Africa was 34 years ago in the Eastern Cape, according to the NICD. The NICD has asked people not to handle live or dead rodents.
Prof Lise Korsten (Tel: +27 12 420 3295 / Cell: 079 522 8476 / Email: Lise.Korsten@up.ac.za)
Professor in the Department of Microbiology and Plant Pathology at the University of Pretoria
About the author:
Prof Korsten is a full professor in the Department of Microbiology and Plant Pathology at the University of Pretoria and has more than 20 years of experience working on fresh produce focusing on postharvest disease, food safety and disease diagnostics using molecular methods. She has published 73 peer-reviewed papers and 11 invited book chapters and has also compiled two series of books for the FAO covering horticultural supply chain management and food safety in selected fruit and vegetable chains. Prof Korsten’s current and future projects focus on food safety for the South African fresh produce industry, postharvest technology aimed at reducing postharvest losses encountered during the fresh produce supply chain and mushroom research.
World Health Organisation: Plague. http://www.who.int/mediacentre/factsheets/fs267/en/
Centres for Disease Control and Prevention: Plague. http://www.cdc.gov/plague/maps/index.html