Zika virus infection – Dominica and Cuba
Between 15 and 16 March 2016, PAHO/WHO was notified of cases of Zika virus infection in Dominica and Cuba.
On 15 March 2016, the National IHR Focal Point of Dominica notified PAHO/WHO of the country’s first autochthonous case of Zika virus infection.
The case is a 28-year-old female who developed symptoms on 1 March and, on 4 March, presented to hospital. Symptoms included retro-orbital pain, frontal headache, mild conjunctivitis, and a rash on the chest and arms. Infection with the Zika virus was confirmed by polymerase chain reaction (PCR) at the sub-regional reference laboratory at the Caribbean Public Health Agency (CARPHA). The patient had no recent history of international travel. No other family members or neighbours are reported to be symptomatic.
Health authorities in Dominica are taking the following measures:
- carrying out environmental investigation and treatment of the dwelling and work places of the case as well as the surrounding environments, including space spraying;
- intensifying public education programs in both the public and private sector;
- continuing national clean-up campaigns;
- continuing communication for healthcare workers;
- mobilizing national and regional resources.
On 16 March 2016, the Ministry of Health of Cuba reported through a press release the country’s first autochthonous case of Zika virus infection.
The case is a 21-year-old resident of Central Havana, Havana province. The patient has no history of travel outside of the country. On 7 March, he developed headache, retro-orbital pain and conjunctivitis. On 9 March, the patient presented to a hospital where his blood samples were collected. On 14 March, Zika virus infection was laboratory confirmed by PCR at the Institute of Tropical Medicine Pedro Kouri.
Health authorities in Cuba are taking the following measures:
- carrying social risk communication;
- strengthening vector control measures and eliminating mosquito breeding sites.
WHO risk assessment
The detection of autochthonous cases of Zika virus infection indicates that the virus is spreading geographically to previously unaffected areas (Dominica and Cuba). 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 Dominica and Cuba based on the current information available.