There is much that we do not know about the transmission of the Zika Virus which was first isolated from a non-human primate in the Zika Forest in Africa. Similar to other viruses such as West Nile Virus and Japanese Encephalitis Virus, these arboviruses utilize mosquitoes as vectors of transmission. That means when a mosquito takes a blood meal from an infected animal, the virus is taken into the mosquito's gut and starts replicating. Thus the mosquitoes are 'biological vectors'. When an infected mosquito bites a human, the virus could be transmitted and infect that human. What is not clear is whether humans can be involved in further transmission to other mosquitoes. For example, is there enough virus in the blood for a mosquito to pick up and continue the transmission to other hosts? With many other arboviruses, humans are considered 'dead end hosts' because there is not sufficient virus in the blood for other mosquitoes to become infected by and transmit to other hosts.
Because the virus utilizes the circulatory system as a means of dissemination to the target organ such as the central nervous system, exposure to blood from other sources could lead to infection. It has been reported that in some cases infection can lead to hematospermia (blood in the ejaculate) and this has resulted in transfer of the virus to the sexual partner. In fact the virus may be secreted in other fluids such as saliva and urine even without blood as has been shown with West Nile Virus present in urine.
The natural hosts of this virus remain to identified. Natural hosts usually show no signs of disease and are important in maintaining the transmission cycle in the wild. Whether certain birds or small mammals are important in this natural cycle remain to be seen.
Because the virus utilizes the circulatory system as a means of dissemination to the target organ such as the central nervous system, exposure to blood from other sources could lead to infection. It has been reported that in some cases infection can lead to hematospermia (blood in the ejaculate) and this has resulted in transfer of the virus to the sexual partner. In fact the virus may be secreted in other fluids such as saliva and urine even without blood as has been shown with West Nile Virus present in urine.
The natural hosts of this virus remain to identified. Natural hosts usually show no signs of disease and are important in maintaining the transmission cycle in the wild. Whether certain birds or small mammals are important in this natural cycle remain to be seen.
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