Zika virus infection – Saint Lucia
On 7 April 2016, the National IHR Focal Point of Saint Lucia notified PAHO/WHO of the first 2 confirmed cases of locally-acquired Zika virus infection.
- The first case is a 25-year-old male from the Castries district. On 16 March, he experienced fever, pain (joint, head, waist), neck stiffness and lymphadenopathy. Blood samples were collected on 17 March.
- The second case is a 28-year-old pregnant female from the Castries district in Saint Lucia. On 6 March, she experienced fever and rash (chest, hands, wrists, fingers, bottoms of her feet). She was at 9 weeks of gestation at the time of symptom onset. Blood samples were collected on 10 March.
On 29 March, blood samples were sent to the Caribbean Public Health Agency (CARPHA) for testing and, on 6 April, samples were confirmed positive for Zika virus by real-time polymerase chain reaction (RT-PCR). None of the cases had recent travel history.
Public health response
To date, the Ministry of Health of Saint Lucia has implemented the following public health measures:
- conducting stakeholder consultations with
- the public and private sectors as well as nongovernmental organizations that focus on vector borne disease;
- with the tourism sector (Tourist Board, Ministry of Tourism and St. Lucia Hotel and Tourism Association) that led to a collaborative action plan to reduce the possible economic and health impact of Zika Virus;
- carrying out public awareness campaigns to encourage the public to take action to reduce the breeding of mosquitoes in and around their homes and within their communities;
- organizing clean-up campaigns in collaboration with private and public sector organizations to remove sources of mosquito breeding and to disseminate information on mosquito borne disease prevention;
- strengthening antenatal care to reduce the impact of Zika Virus on neonatal health by providing bed nets to antenatal clinics at the community level, with assistance of PAHO;
- training health care workers and preparing facilities to manage potential congenital malformations (e.g., Guillain-Barre Syndrome and microcephaly);
- strengthening surveillance for Zika virus, microcephaly and Guillain-Barre Syndrome at the two main public hospitals;
- conducting routine Vector control measures.
WHO risk assessment
The detection of autochthonous cases of Zika virus infection indicates that the virus is spreading geographically to previously unaffected areas (Saint Lucia). The notification of autochthonous transmission in a new country does not change the overall risk assessment. The risk of a global spread of Zika virus to areas where the competent vectors, the Aedes mosquitoes, are present is significant given the wide geographical distribution of these mosquitoes in various regions of the world. WHO continues to monitor the epidemiological situation and conduct risk assessment based on the latest available information.
The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for Zika virus infection. Prevention and control relies on reducing the breeding of mosquitoes through source reduction (removal and modification of breeding sites) and reducing contact between mosquitoes and people. This can be achieved by reducing the number of natural and artificial water-filled habitats that support mosquito larvae, reducing the adult mosquito populations around at-risk communities and by using barriers such as insect screens, closed doors and windows, long clothing and repellents. Since the Aedes mosquitoes (the primary vector for transmission) are day-biting mosquitoes, it is recommended that those who sleep during the daytime, particularly young children, the sick or elderly, should rest under mosquito nets (bed nets), treated with or without insecticide to provide protection. Mosquito coils or other insecticide vaporizers may also reduce the likelihood of being bitten.
During outbreaks, space spraying of insecticides may be carried out following the technical orientation provided by WHO to kill flying mosquitoes. Suitable insecticides (recommended by the WHO Pesticide Evaluation Scheme) may also be used as larvicides to treat relatively large water containers, when this is technically indicated.
Basic precautions for protection from mosquito bites should be taken by people traveling to high risk areas, especially pregnant women. These include use of repellents, wearing light colored, long sleeved shirts and pants and ensuring rooms are fitted with screens to prevent mosquitoes from entering.
Although the risk of transmission of Zika virus through sexual activity is considered to be very limited, based on precautionary principles, WHO recommends the following:
- All patients (male and female) with Zika virus infection and their sexual partners (particularly pregnant women) should receive information about the potential risks of sexual transmission of Zika virus, contraceptive measures and safer sexual practices, and should be provided with condoms when feasible. Women who have had unprotected sex and do not wish to become pregnant because of concern with infection with Zika virus should also have ready access to emergency contraceptive services and counselling.
- Sexual partners of pregnant women, living in or returning from areas where local transmission of Zika virus is known to occur, should use safer sexual practices or abstinence from sexual activity for the duration of the pregnancy.
- As most Zika virus infections are asymptomatic:
- Men and women living in areas where local transmission of Zika virus is known to occur should consider adopting safer sexual practices or abstaining from sexual activity.
- Men and women returning from areas where local transmission of Zika virus is known to occur should adopt safer sexual practices or consider abstinence for at least four weeks after return.
Independently of considerations regarding Zika virus, WHO always recommends the use of safer sexual practices, including the correct and consistent use of condoms to prevent HIV, other sexually transmitted infections and unwanted pregnancies.
WHO does not recommend routine semen testing to detect Zika virus.
WHO does not recommend any travel or trade restriction to Saint Lucia based on the current information available.