Date: Fri 19 Jan 2018
Source: WHO [edited]
On [3 Jan 2018], the Ministry of Health of Senegal notified WHO of a case of Rift Valley fever (RVF) reported from a hospital in Dakar. On [29 Dec 2017], a blood sample taken from a 52-year-old Korean man, resident in the Gambia, done at the Institute Pasteur Dakar, was positive for RVF on IgM testing. Previous PCR testing had been negative for RVF and other arboviruses.
The case patient worked for a fishing company in the Gambia and had no known history of handling raw meat. On [5 Dec 2017], the case patient travelled with his brother and 2 colleagues from Banjul, the Gambia, to Ziguinchor, Senegal. On [8 Dec 2017], the case patient continued travelling with his brother, a colleague, and a driver, from Ziguinchor to Bissau, Guinea-Bissau, and continued to Buba the following day. On [10 Dec 2017], the case patient returned from Buba to Bissau, and presented with a dry cough, fever, headache, and joint pain. His brother and the driver also developed a dry cough on [10 Dec 2017], which improved the following day. The group returned to the Gambia (via Ziguinchor) on [12 Dec 2017].
The case patient, however, continued to suffer a persistent cough during this time. On his return to Banjul, he additionally developed fever, headache, and vertigo. He was hospitalized on [20 Dec 2017] and diagnosed with severe malaria. On [23 Dec 2017], he became delirious and developed psychomotor agitation, profuse mucousy diarrhoea, bile-stained vomiting, and haemorrhage. On [25 Dec 2017], he became comatose and was evacuated by ambulance to Dakar. His symptoms improved, and blood samples were taken on 26, 28, and 30 Dec 2017. However, he experienced a recurrence of haemorrhagic symptoms on 31 Dec 2017 and died the same day.
Public health actions
A case investigation was conducted by a multidisciplinary team from the Centre of Health Emergency Operations of the Ministry of Health of Senegal. As part of this investigation, blood samples were collected from the brother of the case and the colleague and driver who accompanied him to Guinea-Bissau. These samples were all negative for RVFV by PCR. The results of the investigation and recommendations for action from the Ministry of Health of Senegal are pending. A case investigation was conducted by a multidisciplinary team from the Epidemic and Disease Control Unit of the Ministry Health of the Gambia. Enhanced RVF surveillance in the animal population and community RVF sensitization have been implemented in the country.
Outbreaks of RVF are uncommon in the Gambia and its neighbouring countries. The last documented human case of RVF in the Gambia was reported in 2002. There is currently no indication of risk of a major RVF outbreak in the Gambia, Senegal, or Guinea-Bissau. Heavy rainfall, causing flooding and mass emergence RVF vectors, _Aedes_ and _Culex spp._ mosquitoes, is closely associated with RVF outbreaks. Uncontrolled movement of livestock can increase the risk of spread of the disease to new areas. RVF can cause trade reductions and important economic losses due to high mortality and abortion rates among infected livestock. Integrated control measures that address both human and animal health are therefore necessary (e.g. preventive animal vaccination, vector control, control of animal movements, educational campaigns for populations at risk).
[The case, who travelled in 3 different countries (The Gambia, Senegal, and Bissau) was diagnosed as being affected by malaria. Later, this person and people accompanying him exhibited symptoms that can be attributed to RVF. However, all of the other 3 tested negative, while the case was diagnosed RVF positive on IgM testing and negative on PCR. The situation needs some clarification, especially since it is not the flooding season in the region, which favors the multiplication of disease vector insects and thereby precipitates the appearance of RVF in animals with possible contamination of humans. - ProMED Mod.AB]
[Rift Valley fever (RVF) virus can persist for a long time in some areas, maintained in _Aedes_ vector mosquitoes that deposit eggs in seasonally-flooded areas, where those eggs are transovarially infected with the virus. Adult female mosquitoes coming from infected eggs can transmit the virus during their 1st blood meals. Eradicating the virus from these areas is not possible with current technology.
Although ProMED-mail has not previously posted cases of RVF in the Gambia, there is a report from neighboring Senegal. - ProMED Mod.TY]
[Mauritania, a country in close proximity (neighboring with Senegal to its north) has also experience recurrent outbreaks of RVF (see prior ProMED-mail posts). - ProMED Mod.MPP]