ZIKV spreading in Brazil, reported in 19 countries as of January 4 —ECDC
At least 19 countries are reporting local transmission of confirmed Zika virus infections (ZIKV) in the nine months to 4 Jan 2016, reported the European Center for Disease Prevention and Control (ECDC).
Those countries are
Brazil, Cape Verde, Colombia, El Salvador, Fiji, French Guiana, Guatemala, Honduras, Martinique, Mexico, New Caledonia, Puerto Rico, Panama, Paraguay, Samoa, Solomon Islands, Suriname, Vanuatu and Venezuela.
ZIKV in Brazil
The Ministry of Health (MOH) of Brazil is concerned about a possible association between the Zika virus outbreak and increased numbers of babies born with microcephaly (smaller than expected head size).
Brazil reported its first case of ZIKV in May 2015. The virus has since spread rapidly, causing infections in many Brazilian states and other countries in Latin America. The association of Zika virus infection and microcephaly and is still under investigation, said MOH.
Microcephaly in Brazil
Starting in October 2015, the Brazilian MOH received reports of an increase in the number of babies being born with microcephaly. The number of microcephaly cases are roughly 10 times higher than what the country normally sees in a year.
There are no published reports of increased numbers of microcephaly associated with other similar viral (i.e. flaviviral) diseases transmitted by mosquitoes.
ZIKV in Puerto Rico
On December 31, the Puerto Rico Department of Health reported the first locally acquired case of Zika virus infection in Puerto Rico. Zika was confirmed in a resident of Puerto Rico with no known travel history. Health officials in Puerto Rico are monitoring for other cases of Zika virus infection, said CDC.
Zika: Coming To America Through Mosquitoes, Travel, and Sex —Forbes
“…The latest two [viruses] that hit the U.S., chikungunya and dengue, are painful and bad enough — and dengue can kill people who are infected more than once. Zika adds an added nasty punch of perhaps causing microcephaly, a birth defect where babies are born with abnormally small skulls and brains, and often have developmental abnormalities…” (Stone, 1/4).
On Dec. 10, officials in Panama announced the country’s first case of locally acquired ZIKV , which raised the number of countries in the Americas with reported cases of the infections to at least 10
On Dec. 1, the Pan American Health Organization (PAHO) issued an alert concerning the Yellow Fever. Cases had already been reported in Brazil, Chile (on Easter Island), Colombia, El Salvador, Guatemala, Mexico, Paraguay, Suriname and Venezuela.
In light of the circulation of yellow fever in several areas of the Region, and in the context of the ongoing El Niño Southern Oscillation (ENSO) the Pan American Health Organization/World Health Organization ( PAHO/WHO) advises Member States to establish and maintain the capacity to detect and confirm cases of yellow f ever and keep health professionals up to date to enable them to identify suspected cases and manage cases properly, especially in areas at risk for yellow fever. In addition, M ember States are advised to maintain high vaccination coverage in at risk populations.
INTRODUCTION [ECDC]
Zika virus disease is a mosquito-borne disease caused by Zika virus (ZIKV) which causes in general a mild febrile illness with maculo-papular rash. Aedes mosquitoes are considered as main vectors. Before 2007, viral circulation and a few outbreaks were documented in tropical Africa and in some areas in Southeast Asia. Since 2007, several islands of the Pacific region have experienced outbreaks. In 2015, ZIKV disease outbreaks were reported in South America for the first time. ZIKV disease is now considered as an emerging infectious disease.
A significant increase of patients with Guillain–Barré syndrome (GBS) was reported during the 2014 outbreak in French Polynesia. A similar increase along with an unusual increase of congenital microcephaly was observed in some regions in north eastern Brazil in 2015. Causal relationships are currently under investigation.
There is no prophylaxis, treatment or vaccine to protect against ZIKV infection. Therefore, preventive personal measures are recommended to avoid mosquito bites during the daytime. http://ecdc.europa.eu/en/healthtopics/zika_virus_infection/factsheet-health-professionals/Pages/factsheet_health_professionals.aspx#sthash.2cnQku6v.dpuf
THE PATHOGEN
- Zika virus (ZIKV) disease is caused by a virus from the Flavivirus genus, Flaviviridae family, from the Spondweni group.
- It was first isolated in 1947 from a monkey in the Zika forest, Uganda, then in mosquitoes (Aedes africanus) in the same forest in 1948, and in a human in Nigeria in 1952. There are two ZIKV lineages: the African lineage and the Asian lineage which has recently emerged in the Pacific and the Americas. [1,2]
CLINICAL FEATURES AND SEQUELAE
- The incubation period ranges between approximately three to 12 days after the bite of an infected mosquito.
- Most of the infections remain asymptomatic (between 60 to 80%).
- Disease symptoms are usually mild and the disease in usually characterised by a short-lasting self-limiting febrile illness of 4–7 days duration without severe complications, with no associated fatalities and a low hospitalisation rate.
- The main symptoms are macular or papular rash, fever, arthralgia, non-purulent conjunctivitis/conjunctival hyperaemia, myalgia and headache. The maculo-papular rash often starts on the face and then spreads throughout the body. Less frequently, retro-orbital pain and gastro-intestinal signs are present.
Auto-immune, neurological and neurodevelopmental conditions such as Guillain-Barré syndrome and microcephaly in foetuses and newborns from mothers possibly exposed to ZIKV in the two first trimesters of the pregnancy were notified during recent Zika disease outbreaks (French Polynesia and Brazil). Further evidence is needed to establish a causal link between these neurological/neurodevelopmental impairments and infections with ZIKV.
EPIDEMIOLOGY
- Serological surveys in Africa and Asia indicate a most likely silent ZIKV circulation with detection of specific antibodies in various animal species (large mammals such as orangutans, zebra, elephants, water buffaloes) and rodents.
- The knowledge of geographical distribution of ZIKV is based on results of serosurveys and viral isolation in mosquitoes and humans, and with reports of travel-associated cases and very few published outbreaks. Before 2007, the areas with reported ZIKV circulation included tropical Africa and Southeast Asia.
- An outbreak was reported on Yap Island, Federated States of Micronesia (FSM) from April to July 2007 [3]. This was the first outbreak of ZIKV identified outside of Africa and Asia. Between 2013 and 2015, several significant outbreaks were notified on islands and archipelagos from the Pacific region including a large outbreak in French Polynesia. In 2015, ZIKV emerged in South America with widespread outbreaks reported in Brazil and Columbia [1,4,5].
TRANSMISSION
- Zika virus is transmitted by mosquitoes. It has been isolated from Aedes aegypti mosquitoes and experimental infections show that this species is capable of transmitting ZIKV.
- Other Aedes mosquito species (notably Ae. africanus, Ae. albopictus, Ae. polynesiensis, Ae. unilineatus, Ae. vittatus and Ae. hensilli) are considered as potential vectors of ZIKV. These species bite during the day (especially in mid-morning and between late afternoon and twilight).
- Additional modes of transmission have been identified. Perinatal transmission can occur most probably by trans-placental transmission or during delivery when the mother is infected. Sexual transmission was reported in two case reports.
- There is a potential risk of ZIKV transfusion-derived transmission.
- More information on mosquitoes can be found here: Aedes albopictus and Aedes aegypti. [1,6-8]
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