Malaria@India

INTRODUCTION

• Malaria is a potentially life threatening parasitic disease. caused by parasites known as Plasmodium viviax (P.vivax), Plasmodium falciparum (P.falciparum), Plasmodium malariae (P.malariae) and Plasmodium ovale (P.ovale)

• It is transmitted by the infective bite of Anopheles mosquito

• Man develops disease after 10 to 14 days of being bitten by an infective mosquito

• There are two types of parasites of human malaria, Plasmodium vivax, P. falciparum, which are commonly reported from India.

• Inside the human host, the parasite undergoes a series of changes as part of its complex life cycle. (Plasmodium is a protozoan parasite)

• The parasite completes life cycle in liver cells (pre-erythrocytic schizogony) and red blood cells (erythrocytic schizogony)

• Infection with P.falciparum is the most deadly form of malaria.

HISTORICAL PERSPECTIVE

Malaria has been a major public health problem in India. Intermittent fever, with high incidence during the rainy season, coinciding with agriculture, sowing and harvesting, was first recognized by Romans and Greeks who associated it with swampy areas. They postulated that intermittent fevers were due to the ‘bad odour’ coming from the marshy areas and thus gave the name ‘malaria’ (‘mal’=bad + ‘air’) to intermittent fevers. In spite of the fact that today the causative organism is known, the name has stuck to this disease.

MAGNITUDE OF THE PROBLEM

1.87 million cases of malaria (including 0.86million P.falciparum cases) and 1006 deaths were reported from the country in 2003.

Provisional data for the year 2004 reveals that the largest numbers of cases in the country were reported by Orissa, followed by Gujarat, Chhattisgarh, West Bengal, Jharkhand, Karnataka, Uttar Pradesh and Rajasthan and the largest numbers of deaths were reported by Orissa, followed by West Bengal, Mizoram, Jharkhand, Meghalaya, Karnataka, Tripura and Assam.

SYMPTOMS OF MALARIA

• Typically, malaria produces fever, headache, vomiting and other flu-like symptoms.

• The parasite infects and destroys red blood cells resulting in easy fatigue-ability due to anemia, fits/convulsions and loss of consciousness.

• Parasites are carried by blood to the brain (cerebral malaria) and to other vital organs.

• Malaria in pregnancy poses a substantial risk to the mother, the fetus and the newborn infant. Pregnant women are less capable of coping with and clearing malaria infections, adversely affecting the unborn fetus.

SYMPTOMS OF SEVERE AND COMPLICATED MALARIA

The priority requirement is the early recognition of signs and symptoms of severe malaria that should lead to prompt emergency care of patient. The signs and symptoms that can be used are non-specific and may be due to any severe febrile disease, which may be severe malaria, other severe febrile disease or concomitant malaria and severe bacterial infection.

The symptoms are a history of high fever, plus at least one of the following:-

• Prostration (inability to sit), altered consciousness lethargy or coma

• Breathing difficulties

• Severe anaemia

• Generalized convulsions/fits

• Inability to drink/vomiting

• Dark and/or limited production of urine

Patients with prostration and/or breathing difficulties should, if at all possible, be treated with parenteral antimalarials and antibiotics. Oral treatment should be substituted as soon as reliably possible. Frequent monitoring of laboratory parameters is essential – blood sugar, blood urine, fluid balance, associated infection, etc. Drugs that increase gastro intestinal bleeding should be avoided.

SIGNS OF SEVERE AND COMPLICATED MALARIA

• Cerebral malaria, defined as unarousable coma not attributable to any other cause in a patient with falciparum malaria.

• Generalized convulsions.

• Normocytic anaemia.

• Renal failure.

• Hypoglycaemia.

• Fluid, electrolyte and acid-base disturbances.

• Pulmonary oedema.

• Circulatory collapse and shock (“algid malaria”).

• Spontaneous bleeding (disseminated intravascular coagulation).

• Hyperpyrexia.

• Hyperparasitaemia.

• Malarial haemoglobinuria.

RISK FOR SEVERE COMPLICATIONS

• In areas of low transmission – all age groups are vulnerable but adults develop more severe and multiple complications. The transmission pattern in most parts of India is usually low, but intense transmission is seen in north-eastern states and large areas of Orissa, Chattisgarh, Jharkhand and Madhya Pradesh.

• In areas of high transmission – children below 5 years, visitors, migratory labour.

• Association of pregnancy-pregnant women are less capable of coping with and clearing malaria infections, adversely affecting the unborn fetus.

LIFE CYCLE OF MALARIA PARASITE IN MAN AND MOSQUITO

• Relapse in P.vivax and P.ovale are due to persistent hepatic cycle.

• Recrudescence in P.falciparum is due to persistent erythrocytes cycle.

Trend of Malaria Cases and Deaths in India

VECTORS OF MALARIA

• There are many vectors of malaria

• Anopheles culicifacies is the main vector of malaria in rural India and Anopheles stephensi in urban India

• Anopheles minimus is an efficient vector in the North-Eastern region and Anopheles fluviatilis in hill and foot hill areas.

1. Feeding habits

• It is a zoophilic species

• When high densities build up relatively large numbers feed on human beings

2. Resting habits

• Rests during daytime in human dwellings and cattlesheds

3. Breeding places

• Breeds in rainwater pools and puddles, borrowpits, river bed pools, irrigation channels, seepages, rice fields, wells, pond margins, sluggish streams with sandy margins.

• Extensive breeding is generally encountered following monsoon rains.

4. Biting time

• Biting time of each vector species is determined by its generic character, but can be readily influenced by environmental conditions.

• Most of the vectors, including Anopheles culicifacies, start biting soon after dusk. Therefore, biting starts much earlier in winter than in summer but the peak time varies from species to species.

MALARIA CONTROL STRATEGIES

1. Early case Detection and Prompt Treatment (EDPT)

• EDPT is the main strategy of malaria control – radical treatment is necessary for all the cases of malaria to prevent transmission of malaria.

• Chloroquine is the main anti-malaria drug for uncomplicated malaria.

• Drug Distribution Centres (DDCs) and Fever Treatment Depots (FTDs) have been established in the rural areas for providing easy access to anti-malarial drugs to the community.

• Alternative drugs for chloroquine resistant malaria are recommended as per the drug policy of malaria.

2. Vector Control

(i) Chemical Control

• Use of Indoor Residual Spray (IRS) with insecticides recommended under the programnme

• Use of chemical larvicides like Abate in potable water

• Aerosol space spray during day time

• Malathion fogging during outbreaks

(ii) Biological Control

• Use of larvivorous fish in pond, ornamental tanks, fountains etc.

• Use of biocides.

(iii) Personal Prophylatic Measures that individuals/communities can take up

• Use of mosquito repellent creams, liquids, coils, mats etc.

• Screening of the houses with wire mesh

• Use of bednets treated with insecticide

• Wearing clothes that cover maximum surface area of the body

4. Community Participation

• Sensitizing and involving the community for detection of Anopheles breeding places and their elimination

• Involving NGOs in programme strategies

• Collaboration with CII/ASSOCHAM/FICCI

5. Environmental Management & Source Reduction Methods

• Source reduction i.e. filling of the breeding places

• Proper covering of stored water

• Channelization of breeding source

6. Monitoring and Evaluation of the programme

• Monthly Computerized Management Information System (CMIS)

• Field visits by State and National Programme Officers

• Field visits by Malaria Research Centres and other ICMR Institutes

• Feedback to states on field observations for corrective action.