malaria vector mosquito life cycle

Life Cycle
Normally embryonic development is completedwithin a few hours after egg laying, and the first instar larvae hatch. Fully developed larvae of Aedes remain in the egg shell until eggs are flooded, and can thereby be stored for a long period of time (depending on temperature and humidity up to 4.5 years). Larvae are aquatic, mainly occurring in fresh water, but some species also develop in salt water. The size of the habitat can be very small, e.g. tree holes. The total duration of the four larval instars varies greatly, even within one species, especially depending on temperature and food supply. In the tropics it can be completed within one week, in temperate regions many months and even longer if a larval diapause exists.
Some species are even frost-tolerant while others live at 50_C. The larvae feed on debris or plankton (filter feeders) or predate other larvae. The development of the also aquatic pupa is also temperature- dependent, lasting between 1 day or up to three weeks. If the pupae are disturbed, they actively swim downwards with their paddles at the end of the abdomen. The longevity of the adults strongly varies according to the climatic region, on average one to two weeks in the tropics and four to five weeks in temperate regions, but up to several months for females of hibernating or aestivating species. Thereby, the whole developmental cycle (egg to egg) can last about 7 days or up to several months in diapausing species.
Distribution Mosquitoes are found almost worldwide in almost all types of ecological zones, being absent only from Antarctica and some islands.

Mosquito vector in malaria- Anopheles,culex

General Information

Fossil mosquitoes are about 50 million years old, which is much time to adapt to the later developing human. All human populations are affected by mosquitoes, mainly by bites but also by the transmission of diseases. About 3500 mosquitoes belong to the family Culicidae, the most important genera ?Anopheles and ?Culex, ?Mansonia and ?Aedes belonging to the subfamilies Anophelinae and Culicinae, respectively. Mosquitoes were the first insects in which a causative agent of a disease, ?Bancroftian filariasis, was observed (1877). Meanwhile they are known as vectors of many diseases, e.g. viral and bacterial diseases,

But are mostly known as vectors of malaria. Mosquitoes are holometabolous insects, larvae

And pupae live aquatically. Adults are about 5 mm long, holding their wings flat above their body. In this dipteran group, only females suck blood. The adults can be distinguished from non-blood-sucking Nematocera, e.g. chironomids, by scales on the wing veins and especially by the long, forwardly directed proboscis.

Prevention and control of malaria

Area visited Prophylactic regimen Alternatives
No chloroquine resistance / Chloroquine 300 mg weekly/Proguanil 200 mg daily
Limited chloroquine resistance
Significant chloroquine / Chloroquine 300 mg weekly /Doxycycline 100 mg daily Or
resist -Proguanil 200 mg daily /Mefloquine 250 mg weekly
-Mefloquine 250 mg weekly /Doxycycline 100 mg daily
or
Malarone 1 tablet daily

Management of malaria

Drug treatment of uncomplicated malaria in adults
Plasmodium vivax, P. ovale, P. malariae, CQ-sensitive P. falciparumChloroquine:600 mg300 mg 6 hours later300 mg 24 hours later
300 mg 24 hours later
CQ-resistant, SP-sensitive P. falciparum Fansidar (SP): 3 tablets as single doseCQ- and SP-resistant P. falciparum Quinine: 600 mg 3 times daily for 7 days plus Tetracycline: 500 mg 4 times daily for 7 days or Fansidar (SP): 3 tablets as single dose
Alternative therapies
Mefloquine: 20 mg/kg in 2 doses 8 hours apart or Malarone: 4 tablets daily for 3 days or Coartemether: 4 tablets 12-hourly for 3 days or Lapdap (chlorproguanil/dapsone)
ollowing successful treatment of P. vivax or P. ovale malaria, it is necessary to give a 2- to 3-week course of primaquine (15 mg daily) to eradicate the hepatic hypnozoites and prevent relapse. This drug can precipitate haemolysis in patients with G6PD deficiency

Diagnosis of malaria

Diagnosis

Malaria should be considered in the differential diagnosis of anyone who presents with a febrile illness in, or having recently left, a malarious area. Falciparum malaria is unlikely to present more than 3 months after exposure, even if the patient has been taking prophylaxis, but vivax malaria may cause symptoms for the first time up to a year after leaving a malarious area.
Diagnosis is usually made by identifying parasites on a Giemsa-stained thick or thin blood film (thick films are more difficult to interpret, and it may be difficult to speciate the parasite, but they have a higher yield). At least three films should be examined before malaria is declared unlikely. An alternative microscopic method is quantitative buffy coat analysis (QBC), in which the centrifuged buffy coat is stained with a fluorochrome which 'lights up' malarial parasites. A number of antigen-detection methods for identifying malarial proteins and enzymes have been developed. Some of these are available in card or dipstick form, and are potentially suitable for use in resource-poor settings. Serological tests are of no diagnostic value.
Parasitaemia is common in endemic areas, and the presence of parasites does not necessarily mean that malaria is the cause of the patient's symptoms. Further investigation, including a lumbar puncture, may be needed to exclude bacterial infection.