Describe symptoms of Malaria?? Which Mosquito species spread malaria over india?
Answers
Answer:
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Malaria
Cause
Malaria is caused by the protozoan parasite Plasmodium. Human malaria is caused by four different species of Plasmodium: P. falciparum, P. malariae, P. ovale and P. vivax.
Humans occasionally become infected with Plasmodium species that normally infect animals, such as P. knowlesi. As yet, there are no reports of human-mosquitohuman transmission of such “zoonotic” forms of malaria.
Transmission
The malaria parasite is transmitted by female Anopheles mosquitoes, which bite mainly between dusk and dawn.
Nature of the disease
Malaria is an acute febrile illness with an incubation period of 7 days or longer. Thus, a febrile illness developing less than 1 week after the first possible exposure is not malaria.
The most severe form is caused by P. falciparum; variable clinical features include fever, chills, headache, muscular aching and weakness, vomiting, cough, diarrhoea and abdominal pain. Other symptoms related to organ failure may supervene, such as acute renal failure, pulmonary oedema, generalized convulsions, circulatory collapse, followed by coma and death.The initial symptoms, which may be mild, may not be easy to recognize as being due to malaria.
It is important that the possibility of falciparum malaria is considered in all cases of unexplained fever starting at any time between 7 days after the first possible exposure to malaria and 3 months (or, rarely, later) after the last possible exposure. Any individual who experiences a fever in this interval should immediately seek diagnosis and effective treatment, and inform medical personnel of the possible exposure to malaria infection. Falciparum malaria may be fatal if treatment is delayed beyond 24 h after the onset of clinical symptoms.
Young children, pregnant women, people who are immunosuppressed and elderly travellers are particularly at risk of severe disease. Malaria, particularly P. falciparum, in non-immune pregnant travellers increases the risk of maternal death, miscarriage, stillbirth and neonatal death.
The forms of human malaria caused by other Plasmodium species cause significant morbidity but are rarely life-threatening. Cases of severe P. vivax malaria have recently been reported among populations living in (sub)tropical countries or areas at risk. P. vivax and P. ovale can remain dormant in the liver. Relapses caused by these persistent liver forms (“hypnozoites”) may appear months, and rarely several years, after exposure. Relapses are not prevented by current chemoprophylactic regimens, with the exception of primaquine. Latent blood infection with P. malariae may be present for many years, but it is very rarely life-threatening.
In
Most cases of falciparum malaria in travellers occur because of poor adherence to, or complete failure to use medicines, or use of inappropriate prophylactic malaria drug regimens, combined with failure to take adequate precautions against mosquito bites. Studies on travellers’ behaviour have shown that adherence to treatment can be improved if travellers are informed of the risk of infection and believe in the benefit of prevention strategies. Late-onset vivax and ovale malaria may occur despite effective prophylaxis, as they cannot be prevented with currently recommended prophylactic regimens which act only against blood-stage parasites.
Malaria risk is not evenly distributed where the disease is prevalent. Travellers to countries where the degree of malaria transmission varies in different areas should seek advice on the risk in the particular zones that they will be visiting. If specific information is not available before travelling, it is recommended that precautions appropriate for the highest reported risk for the area or country should be taken; these precautions can be adjusted when more information becomes available on arrival. This applies particularly to individuals backpacking to remote places and visiting areas where diagnostic facilities and medical care are not readily available. Travellers staying overnight in rural areas may be at highest risk.
Precautions
Travellers and their advisers should note the four principles – the ABCD – of malaria protection:
Be Aware of the risk, the incubation period, the possibility of delayed onset, and the main symptoms.
Avoid being Bitten by mosquitoes, especially between dusk and dawn.
Take antimalarial drugs (Chemoprophylaxis) when appropriate, to prevent infection from developing into clinical disease.
Immediately seek Diagnosis and treatment if a fever develops 1 week or more after entering an area where there is a malaria risk and up to 3 months (or, rarely, later) after departure from a risk area.
Only certain species of mosquitoes of the Anopheles genus—and only females of those species—can transmit malaria.
Malaria is caused by a one-celled parasite called a Plasmodium. Female Anopheles mosquitoes pick up the parasite from infected people when they bite to obtain blood needed to nurture their eggs. Inside the mosquito the parasites reproduce and develop. When the mosquito bites again, the parasites contained in the salivary gland are injected and pass into the blood of the person being bitten.
Malaria parasites multiply rapidly in the liver and then in red blood cells of the infected person. One to two weeks after a person is infected the first symptoms of malaria appear: usually fever, headache, chills and vomiting. If not treated promptly with effective medicines, malaria can kill by infecting and destroying red blood cells and by clogging the capillaries that carry blood to the brain or other vital organs.
There are four types of human malaria: Plasmodium vivax, P. malariae, P. ovale and P. falciparum. P. vivax and P. falciparum are the most common forms. Falciparum malaria—the most deadly type—is most common in sub-Saharan Africa, where it causes more than 400 000 deaths a year.
In recent years, some human cases of malaria have also occurred with Plasmodium knowlesi – a species that causes malaria among monkeys and occurs in certain forested areas of South-East Asia.