GENEVA - Most developing countries are not in a position to track seasonal flu, let alone a potentially pandemic strain of swine flu, a World Health Organisation official said Thursday.
"Obviously what we're worried about is that most of the developing countries don't have the systems in place that will even tell us whether H1N1 flu is there," said Ties Boerma, director of health statistics at WHO.
"In most countries there is no good cause of death reporting system, so we do not get any data on any cause of death," Boerma said. "So there is still a big gap in information there that we and our partners are working on but that's a huge undertaking."
The WHO annual health statistics report released on Thursday lists H5N1 bird flu among 18 selected infectious diseases.
But it points out that bird flu, as well as malaria or Japanese encephalitis, is difficult to identify without laboratory testing that is often not available in developing countries.
Mexico had to resort to Canadian testing to detect the swine flu virus. Even in middle income countries, flu cases are often listed as pneumonia.
"So there is no distinction between influenza and pneumonia, let alone what type of influenza it was," said Boerma.
"In many countries it's very difficult. For example, we looked at the Mexican statistics on influenza, but really most of the influenza cases are buried under pneumonia."
Since the new A(H1N1) virus emerged last month in Mexico, health experts have underlined their fears about the virus spreading in the southern hemisphere, especially in poor countries.
Most types of flu are more lethal for those who are weakened by other ailments. Developing countries carry the bulk of the global burden of disease, with impoverished and sparse medical cover.