anopheles mosquito malaria

Last week, all the news channels in Kerala were enthusiastically reporting the detection of five “cerebral malaria” cases in Kozhikode district. All the cases were surprisingly detected in a single house! The newly elected health minister, director of health service department, health secretary and other healthcare workers were concerned. That’s because malaria is a serious and sometimes a fatal preventable disease that affects humans. 

In Africa, children are dying from Malaria at an alarming rate of one child every single minute. According to the latest reports, there were about 198 million cases of malaria in the year 2013 and an estimated 584,000 persons died from the disease.  Things are not so different even in India. About 22% of the Indian population lives in malaria high transmission areas like Chhattisgarh, Jharkhand, Madhya Pradesh, Orrisa, Andhra Pradesh, Maharashtra, Gujarat, Rajastan, West Bengal and Karnataka.

This article is about Malaria and things that you need to do to stay away from the deadly mosquito transmitted disease.

What should you know about Malaria?

Malaria is a protozoal disease caused by parasites of the genus Plasmodium. It is transmitted to man by infected female Anopheline mosquitoes. Fever is the most common presenting symptom which is peculiar in it’s paroxysmal periodicity. Flu like illness, shaky chills, nausea, muscle aches are also seen in patients. Clinical features can extend from mild to severe illness and depends on species of the parasite, age, patient’s immunity and related socio-economic conditions. If left untreated, malaria can become a fatal disease and has already claimed millions of lives all over the world. The four different species of Plasmodium protozoan causing malaria in humans are :

  • P. Vivax
  • P. Falciparum
  • P. Malariae
  • P. Ovale

How does a person becomes infected with Malaria?

Only the infective female Anopheles mosquitoes are capable of transmitting malaria. The mosquitoes gets infected with the malarial parasite when it feeds on the blood of an infected human. During it’s next blood meal, these parasites gets mixed with the saliva of the mosquito and is injected into the person who is being bitten. Certain stages of the malarial parasite’s life cycle are completed in man, and the rest in mosquitoes.

In man, the parasites are found primarily in the red blood cells and for the same reason, transmission can take place by infected blood transusion, organ transplant, from pregnant women to their unborn foetuses. Malaria is not a contagious disease and hence transmission doesn’t take place by close contact, sharing same room, food etc.

Meet the villain Anopheles Mosquito

Only a few species of anopheles mosquito are regarded as vectors of primary importance. They are

  • An. Culicifacies in rural areas and
  • An. Stephensi in urban areas

The mosquito must live for at least 10 to 12 days after an infective blood meal to become infective. Shallow wells, ponds, cisterns, fountains, overhead tanks are some of the common breeding sites of the Stephensi species. The anopheles mosquitoes bite at night. Malaria is transmitted by the bites of infected female anopheline mosquitoes.

Are you at risk of Malaria?

You should be worried if :

  • You’re living in an area where the transmission of malaria is known to occur at a high rate
  • You’re travelling to an area as mentioned above
  • You’re a pregnant woman. Chances of complications arising before and during delivery are higher in pregnant women who gets infected with the malarial parasite. Congenital malaria in infants is also a dangerous life-threatening condition. Young children are also at increased risk of getting infected.
  • You’re immunosuppressed. If your immunity is suppressed by prescription drugs (like steroids, immunosuppressants) or by diseases like AIDS, diabetes etc.
  • You require frequent blood transfusions (like in thalassemia), chances of transmission via infected blood is higher.

How to identify Malaria from signs and symptoms?

In the early stages the disease is characterised by fever with chills. The interval at which the fever appears and disappears depends on the type of malarial parasite which is causing the disease. Some of the early symptoms can be listed as :

  • Fever
  • Sweats
  • Shaking chills
  • Flu like illness
  • Nausea and Vomiting
  • Muscle aches
  • Headaches
  • Jaundice
  • Diarrhoea

If left untreated, the disease can progress to involve multiple organs like kidneys, liver, brain etc. Symptoms and signs in such cases depends on the organ(s) involved. Examples of such symptoms can be listed as follows :

  • Tiredness
  • Fatigue
  • Mental confusion
  • Seizure
  • Coma —> Death

How long does it take for these symptoms to appear after an infective mosquito bite?

After being bitten by an infective anopheline mosquito, it may take up to 7 days for the first symptoms of malaria to appear in a person. In most cases, the disease manifests in 10 days to 4 weeks time. However, in certain cases, malaria can develop as late as one year after an infective mosquito bite. If you’ve travelled to a malaria endemic area in the last couple of mnths, it’ll be wise to test for the malarial parasites now.

In Vivax and Ovale type of malaria, the parasites can remain dormant in the infected person’s liver for up to 4 years. When these parasites starts invading the red blood cells again, the resulting condition is referred to as “relapsing malaria”.

What should you do if you’re suspecting malaria?

If you have any of the symptoms as mentioned above or if you have travelled to an area where the transmission of malaria is known to be high, you should visit your nearest healthcare centre to do the blood test for malarial parasite.

In a primary health centre, you can ask the healthcare workers to do a blood test to do a peripheral blood smear examination. You just need to give one drop of blood to do the test. The blood drop is obtained by finger prick method and is uniformly soread on a glass slide which is then stained and examined under a microscope.

Serological tests for detecting malarial antigens and antibodies are also available at the laboratories. These tests are quite expensive, but the results are obtained rapidly within minutes.

 What are the Treatment options for Malaria?

The good news is that, several anti-malarial prescription drugs have been invented which are effective in treating malaria. The trickiest part is the diagnosis of malaria. If you’re living in an area with high prevalence of malaria or if you’ve recently been to such an area, tell your healthcare provider about it so that the simple test can be done right away.

The type and dosing of medicines used in treating malaria depends on the type of plasmodium parasite, age of the patient, pregnancy status, severity of the disease etc. Some of the commonly used anti-malarial treatment regimens are listed in the table below. Please do not try self treatment without seeking the advice of healthcare professionals. That’s because complete cure is possible only by choosing the right drug, right dosage for the right duration of treatment. Combination therapies are often used in case of P. vivax and P. oval in order to prevent the relapses.

NOTE : Even after completing the treatment, the person should test his/her blood for malarial parasites every month for one year to rule out any relapses.

How can you Prevent malaria?

Fogging to kill mosquito

Only if you could do this right!

If you’re living in a high malaria transmission area, you can do a number of things to protect yourselves from the deadly protozoan. Below is a list of things that you should do :

  • Follow the ten tips mentioned in this article to get rid of mosquitoes (mosquito nets and swatters)
  • Ensure that there are no active breeding sites for the anopheles mosquito by implementing proper waste disposal and drainage mechanism.
  • Use long sleeve shirts, mosquito repellants, mosquito nets, insecticide treated mosquito nets to protect yourselves from mosquito bites especially at night.
  • Screen the air-vents, windows and doors in your house properly
  • Pour mineral oil like kerosene in stagnant water collections like puddles and ponds
  • Grow mosquito larvae eating fishes in shallow wells (common in coastal areas)
  • Become an active participant in your community to eliminate malaria

Tips for travellers to Malaria endemic areas

If you’re travelling to an area where the transmission of malaria is known to be occurring, you should take the following precautions :

Consult your healthcare provider and decide on a chemoprophylactic anti-malarial therapy before travelling. The anti-malarial drug choice will be decided based on your travel plan, medical history, age, pregnancy status etc.

Please go through this article to stay away from mosquito bites during the travel.

NOTE : Presumptive treatment of malaria is no longer recommended. It is advisable only for travellers who are from an non-endemic area, soldiers, etc.

Interesting Reading : Kindle edition : “Prevention from mosquito bites: hit the bugs

What are the malaria prevention activities being done by the government?

The central as well as the state governments have a very important role to play in the control and prevention of malaria.

Mosquito control measures

 

Fogging

Anti-adult and anti-larval insecticides are used in large areas to control the mosquitoes. Fogging, indoor space spraying, indoor residual spraying, compression pipes are some of the commonly used techniques to deliver the insecticides. If you feel that your locality has a high mosquito index, contact your nearest government healthcare institution for support.

Source reduction activities are also planned and carried out at high risk areas in frequent intervals. Healthcare workers visit such areas and through various activities makes sure that active breeding sites for mosquito growth are eliminated.

Health education classes emphasising on personal protection, proper water drainage, waste management are also done by healthcare workers periodically.

Surveillance for malaria cases are done in two ways:

Active surveillance – Every multi-purpose health worker has to visit houses of persons with fever (of all types) and have to collect thick and thin smear for laboratory examinations. The smears are to be taken as soon as the fever cases are reported and if needed, the person has to be given proper medications from the hospital. If laboratory facilities are not available in the area, a rapid bivalent test should be used.

Passive surveillance – This is the surveillance that is being conducted at the clinics and hospitals (like PHC, CHC, TH etc). Peripheral blood smears of persons with fever who visit the hospital are taken at the hospital and sent to the laboratory for examination.

Once a person has been diagnosed with malarial parasite, activities are done in order to control the spread of the disease, provide proper treatment for the person to prevent the progression of the disease from uncomplicated stages to severe life threatening stages. Surveys are done to find more cases in the vicinity of the primary malaria case.

Contact survey –  All the persons in a house where a person has been found to be suffering from malaria needs to be tested for malaria parasite. Bivalent RDT should be used to test the relatives.

Mass survey : Fifty houses located within a half kilometre radius of the affected house should also be targeted for conducting mass surgery. All persons living in these houses, including children should be tested for malarial parasite.

When can we say goodbye to Malaria?

Eradication is the stage when not even a single case of malaria exist in the whole world. That is a goal that will only remain in papers. Many countries have succeeded in eliminating malaria by following strict measures. Vaccines against malaria is still an ongoing research. Many international companies are working on developing an effective malaria vaccine. Vaccines are going to be a revolutionary discovery considering the failure of insecticides, mosquito nets and other mosquito control techniques.

In India, the disease will remain a serious threat to the lives of millions as  long as individual citizens takes the control measures into their own hands. You don’t have to wait for the government to do all the activities while you watch and criticise. Elimination of malaria cannot be achieved without active community participation. Staying away from malaria is in your hands and you need to realise that fact.

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Reference – World health organisation

Dr Prasoon

Dr Prasoon

Author at BeingTheDoctor
Dr Prasoon, founder of BeingTheDoctor is a qualified medical practitioner who finds time to write articles on "health" and his "clinical experiences". He is currently engaged in providing primary health care services in rural India. Learn more in the "about" page.
Dr Prasoon

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