FOR months, officials in provinces afflicted with outbreaks of acute watery diarrhoea, or AWD, have pointed to a longer-than-usual dry season – and the resulting lack of clean water – as a factor behind the mounting cases.
The corollary to that argument has been that the illness should begin to abate with the first rains of the wet season, which came to some provinces in May but have not yet hit everywhere.
Few officials are hoping this holds true more than Dr Chhneang Sovutha, the director of the Health Department in Kratie province, the location of at least 10 deaths from AWD or cholera this year as officials have treated roughly 2,000 cases of AWD.
Last year, Chhneang Sovutha said, there were fewer than 1,000 recorded AWD cases.
“Normally, the diarrhoea cases happen more in the dry season, and this year there have been more cases than last year,” Chhneang Sovutha said Monday.
“The biggest outbreaks of diarrhoea were in March and May, when there was a dry season like I have never seen before in Kratie province.”
But as reports of AWD continue to come in – three men were said to have died last Friday in Mondulkiri province, and 24 fell ill over the weekend in Pursat – some experts say the wet season might not necessarily lead to a drop in cases, and one noted that it could even make things worse, albeit temporarily.
Dr Nima Asgari, a public health specialist for the World Health Organisation, said there was insufficient information to determine how AWD cases fluctuate with the seasons.
But he noted that figures from other countries suggest that the illness is at least partly seasonal.
“When we look at the literature, we see that as the dry season picks up, we see more cases of acute watery diarrhoea,” he said. One of the main reasons for this, he said, might be that open and communal water sources such as ponds – which can become a source of transmission once infected with diarrhoea-causing bacteria – are used more frequently during the dry season.
“Once the rainy season starts, many people use their own freshly collected rainwater,” he said.
But Asgari said there is also some evidence suggesting that AWD can spread more easily during the wet season, particularly towards the beginning of it.
“In a lot of rural places there is no sewage system; there is open defecation,” he said, “so rainwater may get infected and mix with food or water sources. So you may initially see a spike in cases until enough people start collecting their own rainwater.
“You might see an initial increase in cases at the beginning of the season, and then it will settle down.”
Oum Ryna, deputy director of the Department of Meteorology at the Ministry of Water Resources and Meteorology, said Monday that the wet season, which usually begins in May and ends in October, began late this year. Some provinces in the northeast – an area hit particularly hard by AWD – have yet to receive rain, he added.
Asgari said it is too soon to tell if the recent rainfall in other provinces has affected the number of AWD cases. “You’ve got to give it a few weeks,” he said. “You have to consider the life cycle of the transmission cycle.”
Andrew Martin, country manager for Health Unlimited, an NGO that has been assisting health officials in combating AWD in Ratanakkiri, said reports of cases continue to come in, but he expressed hope that the wet season will put a stop to them.
“Really, you’d expect [the number of cases] to go down, but without knowing the source [of the illness], it’s hard to tell,” he said.
Heng Taykry, a secretary of state at Ministry of Health, said that there are a range of factors fuelling AWD, and that some of them, including hygiene, are more important than water supply.
“We have diarrhoea diseases in both seasons – not only the dry season or rainy season – if people are careless with their health,” he said.
“To avoid diarrhoea, all people should drink boiled water, clean their hands and eat hygienic food.”
Between November 2009 and May, the Health Ministry recorded 85,000 cases of AWD, compared to 100,000 in all of 2009, Asgari said.
He added, though, that improved surveillance may partially contribute to higher totals this year.