A Short Review Of The 2009 Cholera Outbreak in Papua New Guinea.

On August 6 2009 a doctor was visiting the remote village of Lambuntina in the Morobe Province of Papua New Guinea (PNG) when he noticed a high number of people with acute onset of watery diarrhea that resulted in death. He notified the Morobe Provincial health authorities to investigate the diarrhea outbreak and a team was mobolised and dispatched to the village of Lambuntina. The outbreak quickly spread to the rest of PNG.

By August 13 2009 multidisciplinary teams were on the ground in the affected village and containment strategies were instituted to prevent further deaths. The diarrhea outbreak was clinically suspected to be cholera. Hence a “suspected case of cholera was defined as acute watery diarrhea or vomiting in a resident of Lambutina or Nambariwa villages since July 22, 2009”. Using this case definition 77 cases were identified. In the two affected villages, 77 cases were identified; attack rates were 14% in Lambutina (48/343) and 5.5% in Nambariwa (29/532). The overall case-fatality ratio was 6.5% (5/77); 2 patients died after they were discharged from the referral hospital.

Ten stool samples were sent for testing, out of which, vibrio cholera was isolated from four samples. Health authorities were not able to determine its origin. After the laboratory results were obtained, the case definition was revised using the World Health Organisation (WHO) standard case definition for cholera. The revised case definition for cholera was someone developing the disease “in an area where the disease is not known to be present, a patient aged 5 years or more develops severe dehydration or dies from acute watery diarrhoea; in an area where there is a cholera epidemic, a patient aged 5 years or more develops acute watery diarrhoea.” These case definitions were supplemented with laboratory data.

Following the initial outbreak a retrospective frequency-matched case-control study was done to identify risk factors associated with cholera. Forty three cases were identified with 43 age-matched controls. This initial assessment showed that close contact with a case from the two affected villages was an independent risk factor. The middle aged and the older population were mostly affected in the initial outbreak. This may have been because of providing care for the sick and handling of dead bodies that resulted in increased exposure.

From a remote village in the Morobe Province, the cholera outbreak quickly spread around the country. By the middle of 2011, the there had been 15 500 reported cholera cases and over 500 deaths. Some of the risk factors for the outbreak and rapid spread around the country were poor access to safe drinking water and poor sanitation. It was also proposed that changes in weather pattern in 2009 may have resulted in increase in plankton which may have facilitated the introduction and outbreak of cholera. Lack of road network around PNG is also thought to have slowed the spread of the infection. Villages close to coastal areas are also at increased risk of cholera.

A case-control study was done by Rosewell and colleagues (2012) to identify the risk factors for cholera in PNG and in their study they found several risk factors. Independent risk factors were age over 20 years, defecating in the open or into a river system and having contact with someone who with a history of travelling to an affected area. Availability of soap and water for hand washing were found to be protective against cholera.

Cholera is transmitted from eating contaminated food, drinking contaminated water or having physical contact with someone with clinical signs and symptoms of cholera. So the prevention strategies are targeted at interrupting the transmission and reducing risk factors associated with the spread of the infection. The initial outbreak in Morobe Province was managed by quickly identifying and treating cases, developing a case definition for cholera, doing a line listing and following up on the contacts to minimize exposure, conducting education and awareness about the disease and how it is transmitted and advice on how to make drinking water safer, for example boiling before drinking. High risk provinces were also identified and prevention and enhanced prevention activities were instituted in these provinces. Cholera vaccine was not used in PNG.

Sometimes in very remote communities in PNG it is not always possible to confirm an outbreak. For example in a diarrhea outbreak in Ambunti District of PNG, there was a diarrhea outbreak but it was not possible to confirm if it was due to cholera or not. I led the medical team that investigated the diarrhea outbreak in Ambunti while working as the site physician for Xstrata Copper – Frieda River Project. Simple basic education messages focusing on hand washing, boiling water and drinking and even prohibiting social interactions such as hand shake, hugging or kissing are also useful in halting a diarrhea outbreak and preventing further spread.

Cholera is an infectious disease that is transmitted by eating contaminated food or drinking contaminated water. In 2009 a cholera outbreak occurred in a remote village in the Morobe Province of PNG and quickly spread to other parts of the country. The outbreak in PNG was managed by identifying and treating cases and preventing spread of the infection by identifying risk factors and interrupting the transmission.


About rodney itaki

Medical doctor and public health specialist from Papua New Guinea.
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