Mosquitoes and malaria - class-IX

W.malayi also called as brugia malayi are the important agents of bancroftian and brugian(it is sometimes referred to as Malayan)filariasis. In contrast to many other mosquito-borne infections of medical significance, lymphatic filariae are transmitted by not just one but by several genera of mosquitoes.

 Female mosquito have mouthparts that pierce food items to enable sucking of internal fluids. In female mosquitoes, all mouthparts are elongated. The labium encloses all other mouthparts like a sheath. The labrum forms the main feeding tube, through which blood is sucked. Paired mandibles and maxillae are present, together forming the stylet, which is used to pierce an animal's skin. During piercing, the labium remains outside the food item's skin, folding away from the stylet. Saliva containing anticoagulants, is injected into the food item and blood sucked out, each through different tubes.

The gametocytes are the sexual stages of Plasmodium that develop in human red blood cells. When a mosquito takes a blood meal, it ingests these gametocytes, making them the infective stage of the parasite for the mosquito vector.

Culex causes filariasis, bird malaria. Its body rests parallel to the surface or substratum. Whereas Anopheles causes malaria. The body is slender and rests at an angle to the surface or substratum.
Therefore, the correct answer is option B.

A malaria control method that targets mosquito larvae and pupae as they mature in standing water could be an important supplementary measure in the fight against the disease. Larval source management (LSM) is a method that targets immature mosquitoes, found in standing water before the females develop into flying adults that are capable of transmitting malaria. This is done by permanently removing standing water, for example by draining or filling land; making temporary changes to mosquito habitats to disrupt breeding, for example by clearing drains to make the water flow; or larviciding by adding chemicals or biological larvicides to standing water to kill larvae.

• Quinine and other cinchona alkaloids including quinidine and cinchonine are effective against malaria.
  
• So, the correct answer is 'Quinine'.

The western mosquitofish (Gambusia affinis) is a species of freshwater fish, also known commonly as simply mosquitofish. Mosquitofish were introduced directly into ecosystems in many parts of the world as a biocontrol to lower mosquito populations, which in turn negatively affected many other species in each distinct bioregion. Based on diet, mosquitofish are classified as larvivorous fish. Their diet consists of zooplankton, small insects and insect larvae, and detritus material. Mosquitofish feed on mosquito larvae at all stages of life. Adult females can consume hundreds of mosquito larvae in one day.

Gametocyte is infective stage for female anopheles mosquito because optimum temperature for growth of gametocyte is present in their body.

The motile zygote formed by fertilization of macro gameteby a micro gameteis called ooKinete. It  occurs in gut of mosquito. 

Mosquitoes cause more human suffering than any other organism. Mosquito acts as a vector for the bacteria and viruses, responsible for the diseases such as malaria, dengue, encephalitis and yellow fever etc. When mosquito bites a human it causes severe skin irritation through an allergic reaction to the mosquito's saliva, this is what causes the red bump and itching.

The causative agent of malaria is Plasmodium vivax and female anopheles act as a vector. 

Malaria is caused by the toxins produced in the human body by malarial parasite Plasmodium. Malarial parasite is carried from the infected to the healthy persons by the female Anopheles mosquito.

Culex is a genus of mosquitoes which carries worms of filariasis, Japanese encephalitis, St. Louis encephalitis, and avian malaria. 
Anopheles is a genus of mosquito first described and named by J. W. Meigen in 1818. About 460 species are recognized, while over 100 can transmit human malaria. Both Culex and Anopheles have three pairs of legs, the last pair is held up in the air while sitting. 

The female Anopheles mosquito, when it withdraws blood the infected malarial patient, the male and female gametes enter into the mosquito gut, when the two male and female gametes fuse together and form a zygote, which develops into ookinetes that burrow into the mosquito midgut wall to develop into oocysts.

There are different ways to prevent mosquito larvae to grow in ponds and rice fields. These can be done by not allowing the water to get stagnant. Also, it can be prevented by inoculating it with Microcystis cyanobacteria. Microcystis aeruginosa causes death of the larvae by producing neurotoxins and hepatotoxins.