Thursday, March 17, 2011

Causes and indications of Malaria and Treatment

                Malaria is a general term applied to a group of diseases caused by infection with specific sporozoan parasites of the genus plasmodium and transmitted to man by certain species of infected female Anopheles mosquito.It is clinically characterized by episodes of  chills and  fever with periods of latency,enlargement of spleen and secondary anaemia.
A typical attack of malaria consists of three successive stages:
1.Cold stage is characterized by sudden onset onset of fever with rigor and chills.This stage lasts between 15 minutes to one hour.
2.Hot Stage is characterized by headache and burning hot and he casts offs clothes.This stage lasts from 2 to 6 hours.
3.Sweating stage is characterized by profuse sweating.This stage lasts from 2 to 4 hours.The febrile paroxysms occur repeatedly after a period of 2 or 3 days depending upon the type of the malaria parasite.Latent period of the disease may be several weeks or months.
Causative agent:
                 Malaria is caused by four distinct species of malaria parasite i.e. Plasmodium vivax,P.falciparum,P.malarae and P.ovole.In india in 70% of cases the causative agent is P.vivax,in 25-30% cases it is P.falciparum while 4-8% cases are due to mixed infection .P.malarae is responsible only for less than 1% of cases in India.The malaria parasite undergoes two cycles of development-Asexul cycle in man and the sexual cycle in mosquito.Man is the intermediate host and mosquito is definitive host.
Mode of transmission:
Following modes are possible for the transmission of malaria.
a)Vector transmission:Malaria is commonly transmitted by the bite of certain species of infected female anopheline mosquitoes.
b)Direct transmission:Malaria can be transmitted by infected needles,blood transfusions etc.
c)Congenital infection: Rarely this can occur in the new born from infected mother.
Incubation period:
The time between mosquito bite and appearance of fever is more than 10 days ranging from 12 to 40 days.
Prevention and control of malaria:
In 1979 the WHO expert Committee on Malaria described the following two categories of antimalarial measures.
I.Measures to be taken by the individual
1.Prevention of man/vector contact by using repellents,protective clothing,bed nets etc.
2.Destruction of adult mosquitoes by domestic sprays.
3.Sestruction of mosquito larvae by peridomestic sanitation,intermittent drying of water containers.
4.Source reduction of mosquitoes by filling,small scale drainage, and other forms of water
5.Measures against malaria parasite which include chemoprophylaxis and chemotherapy.
II.Measures to be taken by the community
1.Prevention of man/vector contact-site selection and screening of houses.
2.Destruction of adult mosquitoes-residual spraying or space spraying of insecticides.
3.Source reduction-prevention of man made malaria,environmental sanitation,water management,drainage schemes.
4.Destruction of mosquito larvae- using larvicides(chemical and biological).
5.Measures against malaria parasite-presumptive treatment,radical,mass drug administration.

        Planning of malaria control should be flexible.Suitable methods should be used in the best way.National Malaria Control Programme was launched in April,1953 by the Government of India.In 1958 the Government changed its strategy from control to eradication and renamed it as National Malaria Eradication Programme.It was very successful up to 1961.After that number of cases began to increase suddenly with increase in the number of deaths also.The situation worsened up to 1976 and then the government has entirely changed the strategy.The programme was 'Modified Plan of Operation 1977' and its objectives were to eliminate the deaths,reduce morbidity and maintain the gains achieved so far,since then the Malaria cases have started coming down and deaths are also
Treatment of malaria:
 All fever cases should be assumed to be due to malaria.Persumptive treatment should be given to all such cases.For this give tablet chloroquine 250 mg(4 tablets stat),simultaneously collect the blood for microscopic examination.If the slide is positive for malaria parasite then radical treatment is given which consists of giving.
1st day:               Chloroquine 600 mg
                          Primaquine 15 mg
Next 4 days:       Primaquine is given in a dose of 15 mg per day.

Antimalarial vaccine:
Vaccination againist malaria is very much desired.Until now no satisfactory vaccine is available against malaria.Many clinical trials are in process to develop a malaria vaccine.

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