Via WHO AFRO's Weekly Bulletin on Outbreaks and Other Emergencies for week 47:
EVENT DESCRIPTION
Health authorities in Angola are observing a gradually increasing number of microcephaly cases, particularly in Luanda Province, where the capital city is located. The event was initially reported in late September 2017 when a cluster of seven cases of microcephaly were detected. However, retrospective investigations established that the initial cases occurred as early as May and June 2017. In November 2017, 10 new cases of microcephaly have been reported.
As of 29 November 2017, a total of 42 cases of microcephaly have been reported, of which 39 occurred in live births and three were in stillbirths. Most of the cases (39, 93%) originated from Luanda Province, especially in the southern part of the city. The other cases came from Zaire Province (1), Moxico Province (1) and Benguela Province (1).
A total of 15 blood specimens were collected either from the newborns or their mothers and sent to the National Public Health Institute laboratory. To date, all the specimens have tested negative for Zika virus by polymerase chain reaction (PCR). Nonetheless, the negative test result does not necessarily rule out the possibility of Zika infection during pregnancy.
In a separate event, two cases of Zika virus infection were confirmed by PCR in Luanda Province in January 2017 – one in an adult with a febrile illness and the other in a stillborn with malformation of the central nervous system. No genotyping of the Zika virus was performed to determine the strain.
PUBLIC HEALTH ACTIONS
• The Ministry of Health is updating the Zika contingency plan, with a focus to strengthen implementation of priority interventions.
• The Ministry of Health is strengthening surveillance for Zika virus infection and its complications in all health facilities, prioritizing antenatal care, obstetrics and paediatric care services in the main hospitals in the country.
• In addition to PCR capability, the Ministry of Health is working to enhance diagnostic testing for Zika infection to include plaque reduction neutralization test (PRNT), which confirm previous Zika virus exposure, as recommended by WHO.
• The Ministry of Health is planning to strengthen control of Aedes aegypti vectors to reduce the risk of Zika virus transmission.
• Case management and patients’ follow up are being strengthened through designated referral hospitals.
• Zika-related risk communication and social mobilization activities are being enhanced, including involvement of local leaders and communities to increase participation in Zika control activities.
SITUATION INTERPRETATION
The incidence of microcephaly appears to be slowly but steadily rising in Angola, particularly in Luanda. The true magnitude of this event is not well understood because of the relatively recent implementation of active surveillance and lack of laboratory confirmation. However, the manifestation of the condition is suggestive of congenital Zika syndrome.
While Zika virus infection was confirmed in Angola in January 2017, there is no evidence to suggest ongoing active transmission. Health authorities have also established that most of the microcephaly cases are coming from populations in lower socio-economic groups, in the suburbs of the city; and that the same areas were previously most affected during the yellow fever outbreak.
More investigations are required in order to gain a better insight into this event. Nonetheless, implementation of priority control measures identified by the Ministry of Health need to commence immediately. Particular focus should be given to enhancing surveillance for early detection, case management in healthcare facilities and ongoing investigations/research.
