Transmission Transmission of malaria occurs when humans get bitten by infected mosquitos carrying the parasite known as Plasmodium falciparum. The saliva from the mosquito transfers the P. falciparum into the blood as sporozoites which then travel to the liver where they are converted to the merozite form and further replicated. After undergoing these changes in the liver, the parasite is then able to infect erythrocytes in the bloodstream. It can take 7 to 30 days after being bitten by a mosquito before symptoms start to arise. It is believed that pregnant women are more susceptible to malaria infection due to being immunocompromised and because infected erythrocytes tend to congregate around the placenta. As a result, the WHO recommends that pregnant women avoid traveling to high endemic regions. Risk Factors The disease results from the aggregation of erythrocytes infected by Plasmodium falciparum which have been shown to adhere to chondroitin sulfate A (CSA) on placental proteoglycans causing them to accumulate in the intervillous spaces of the placenta, blocking the crucial flow of nutrients from mother to embryo. Infected erythrocytes express the VAR2CSA variant of P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) which allows them to bind to CSA on the placenta. The accumulation of infected erythrocytes in the placenta inhibit the exchange of nutrients between the mother and fetus and also causes local inflammation. In areas of high malaria transmission such as Africa, women experiencing their first<unk> es have the highest risk of infection compared to in lower transmission areas where the number of<unk> es has less of an effect on infection rates. This is because women who are pregnant for the first time generally lack antibodies to VAR2CSA on erythrocytes that have been infected by the parasite. Women are most susceptible to malaria infection early on in the first trimester but the risk of infection decreases in the second trimester due to the development of antibodies to the infectious agent over time following the initial exposure. The infection risk also decreases after successive<unk> es. Women that are infected with human immunodeficiency virus (HIV) are also at a high risk of having a higher parasite burden within the placenta during<unk> . This increased parasite burden can show up as increased reporting of symptoms<unk>  with<unk>  and an increased likelihood of adverse maternal and fetal outcomes. There is also an increased risk of an HIV positive woman developing<unk>  in subsequent<unk> es. Although the exact biological mechanism around how HIV and malaria disease states affect each other, it is thought that each condition affects how the immune system reacts to the other condition.
Pregnancy-associated malaria
Malaria
Airport malaria
Toxocariasis
Congenital syphilis
Omsk hemorrhagic fever
Congenital malaria
Brain fever