The Democratic Republic of the Congo (DRC) has had 151 suspected yellow fever cases with 21 deaths since January, with at least some of them linked to the big outbreak in neighboring Angola, the World Health Organization (WHO) said yesterday, citing DRC government sources.
The Angolan outbreak, meanwhile, has expanded to 1,751 cases and 242 deaths, with 582 confirmed cases, the WHO's Regional Office for Africa reported yesterday. On Apr 4 the WHO had put the count of confirmed cases at 490.
Imported cases
In the DRC, the national surveillance system picked up the 151 suspected cases between early January and Mar 22, the WHO said. Nine cases were confirmed by serology in a government lab in Kinshasa. Because possible cross-reactions with other arboviruses can confuse test results, officials sent the positive samples to the Pasteur Institute lab in Dakar, Senegal, for confirmation.
There, four samples tested positive, and three of the cases had been imported from Angola, the WHO said. The cases occurred in Kongo Central Province, which borders Angola.
The WHO noted that yellow fever is endemic in the DRC and that locally transmitted cases have been reported in four provinces since January. But it said the cases in travelers returning from Angola point up the risk of international spread of the disease.
Current information does not suggest the establishment of a cycle of transmission in the DRC, but the presence of vector mosquitoes (Aedes aegypti), the high proportion of people susceptible to the infection, and the volume of population movements to and from Angola pose a serious risk of further spread of the disease, the agency said.
The WHO said all member countries, especially those that harbor A aegypti mosquitoes, should "strengthen the control of immunisation status of travellers to all potentially endemic areas."
In Angola, vaccine in short supply
In Angola, 59 districts in 12 of the 18 provinces have reported yellow fever cases, according to WHO Africa. Of the 582 confirmed cases, 406 were in Luanda province, 85 in Huambo, 22 in Benguela, and the rest in other provinces. Eighteen cases in 10 districts of 5 provinces involve local transmission, the statement said.
The response to the Angolan outbreak has been hampered by a global shortage of yellow fever vaccine. The total stock of vaccine as of Apr 10 was 670,700 doses in the central repository, WHO Africa said.
The agency said about 5.9 million people in Luanda, 90% of the population, have been vaccinated so far. Huambo province was scheduled to launch a vaccination campaign today, targeting 930,751 people over the age of 6 months, while preparations for a vaccination drive were under way in Benguela.
Yellow fever in Uganda, Mauritania
In other developments, yellow fever cases have been reported in Uganda and Mauritania, but it's not clear if they have any connection to the Angola or DRC outbreaks. Uganda adjoins the DRC on the northeast, while Mauritania is on the Atlantic coast in West Africa.
Six cases, with three deaths, have been confirmed in the Masaka district of Uganda, according to Julius Lutwama, PhD, a medical entomologist and virologist with the Uganda Virus Research Institute in Entebbe, who reported the cases yesterday via ProMED-mail, the reporting service of the International Society for Infectious Diseases.
In Mauritania, a single imported yellow fever case has been identified, according to the latest weekly Communicable Diseases Threat Report from the European Centre for Disease Prevention and Control (ECDC), which covers last week. The item does not specify whether the case was imported from Angola.
The ECDC put the number of imported cases in the DRC at 12. It also noted that 10 imported cases have been identified recently in China and 2 in Kenya.
See also:
Apr 11 WHO statement on DRC outbreak
Apr 11 WHO Africa situation update on Angola outbreak
Apr 11 ProMED-mail post on Ugandan cases
ECDC disease threat report for Apr 3-9
Apr 5 CIDRAP News item about yellow fever vaccine shortage
