ABSTRACT
Zika virus disease is a great concern in different parts of the world, and it has become a Public Health Emergency of International Concern. The global pandemic of ZIKV in 2015 prompted concern among scientific community. Zika is a flavivirus of the family Flaviviridae transmitted by mosquitoes. Natural vertical transmission is an ecological strategy that arboviruses adopt to ensure their survival inside the mosquito vector during harsh conditions or interepidemic periods when horizontal transmission is difficult. ZIKV is vertically transmitted from infected females to its offspring. This review has concluded various studies regarding the vertical transmission ability of different mosquito species for ZIKV. Previously Aedes aegypti was considered to be a major vector, however Aedes albopictus and Culex quinquifasciatus are discovered to have the similar vertical transmission potential. Different studies shown that natural vertical transmission has been detected in mosquito species which are not implicated as possible vectors. It leads to the possibility that many other mosquito species may be potential ZIKV vectors.
ABSTRACT
Malaria is a vector borne disease, considered to be one of the most serious public health problems. The present review focused on the blocking of parasite development in mosquito vectors; one broad strategy for achieving this is Transmission Blocking Vaccines (TBV). The TBVs usually rely on immunization of vertebrate hosts with molecules derived from the vector or pathogen to reduce pathogen transmission from infected to uninfected hosts. Most of the studies on the TBVs are based on the antibodies targeted against the surface antigens of sexual stages of malaria parasite, but it is meagre to develop mosquito-based vaccine in this regard. Vector-based TBVs include surface proteins that are expressed by the mosquito midgut digestive enzymes which are induced upon blood-feeding, and receptors expressed on the epithelial line of the tissue. Many proteins are reported that can act as candidates for transmission-blocking vaccines. This review aims to summarize the vector midgut-based proteins identified till date, that can block the development and maturity of sexual stages of the parasite within mosquitoes as targets for transmission-blocking vaccine development. The TBVs intervention can block transmission of different malaria parasite species in various species of mosquitoes with future application perspective worldwide.
ABSTRACT
The effect of anti-mosquito-midgut antibodies on the development of the malaria parasite, P.vivax was studied by feeding the vector mosquito, An. culicifacies with infected blood supplemented with serum from immunized rabbits. In order to get antisera, rabbits were immunized with midgut proteins of three siblings species of Anopheles culicifacies, reported to exhibit differential vectorial capacity. The mosquitoes that ingested anti-midgut antibodies along with infectious parasites had significantly fewer oocysts compared to the control group of mosquitoes. The immunized rabbits generated high titer of antibodies. Their cross reactivity amongst various tissues of the same species and with other sibling species was also determined. Immunogenic polypeptides expressed in the midgut of glucose or blood fed An. culicifacies sibling species were identified by Western blotting. One immunogenic polypeptide of 62 kDa was exclusively present in the midgut of species A. Similarly, three polypeptides of 97, 94 and 58 kDa and one polypeptide of 23 kDa were present exclusively in species B and C respectively. Immunoelectron microscopy revealed the localization of these antigens on baso-lateral membrane and microvilli. The effects of anti-mosquito midgut antibodies on fecundity, longevity, mortality and engorgement of mosquitoes were studied. Fecundity was also reduced significantly. These observations open an avenue for research toward the development of a vector-based malaria parasite transmission-blocking vaccine.