Introduction with burden

Even a century after the discovery of malaria transmission through mosquitoes in India by      Sir, Ronald Ross in 1897, malaria continues to be one of India’s leading pubic health problems. In the 1930s, a treatise written by Sinton on ‘what malaria costs India’ recorded that the problem of the very existence in many parts of India was in fact the problem of malaria. In 1935, it was estimated that 100 million malaria cases and 1 million deaths occurred in India. Another estimate in 1947 suggests that 75 million cases (21.8% population) occurred in the post-independence population of 334 million with some 800,000 deaths. From this point, India achieved spectacular gains in malaria control during the ‘Eradication Era’ in the 1950s till the mid 1960s when reported cases were reduced to 64,000. There were a number of attempts to arrive at the true burden of malaria morbidity and mortality in India. Whereas, National malaria eradication programme (NMEP) reported 5.2 and 2.9 million cases in 1975 and 1980 respectively, the Indian Drug Manufacturers Association estimated 12 million cases in 1975 and 20 million in 1980. From 1990s till date, WHO estimated malaria incidence was 15 million malaria cases with 19500 to 20000 deaths/annum (WHO, SEARO website). According to figures published by the Union Government's National Vector Borne Disease Control Programme (NVBDCP), there were over 1.5 million cases of malaria, more than half of them caused by P. falciparum, and 1,068 deaths in 2009.

According to the National Institute of Malaria Research in 2007, “It is now well accepted that the reported incidence of malaria at the national level on the basis of surveillance carried out in the primary health care system at best reflects a trend and not the true burden of malaria,”. Studies had pointed to deficiencies in coverage, collection and examination of blood smears for signs of infection and in reporting systems. National Institute of Malaria Research (NIMR) Scientist remarks consequently, the actual incidence of malaria in the country was “definitely far more than presently known,”. Deaths due to malaria too were likely to be higher than reported.

Incidence and Prevalence

Estimating the true disease burden of malaria in the country is a challenge, considering its varied epidemiology and dynamics of transmission, said one Indian scientist working on malaria. In its World Malaria Report 2008, the WHO estimated 10.6 million cases of malaria and 15,000 deaths from the disease in India during 2006. (The Government figures put the number of malaria cases at nearly than 1.8 million and deaths at about 1,700 for that year). In India, the upsurge of malaria cases drop down 6.74 million cases in 1976 to 2.1 million cases in 1984. Since 1997, there is a consistently decline trend in the annual malaria.

 The table* shows year-wise reported number of cases and deaths.

  API, Annual parasitic Index

*Government of India, Annual Report 2003-2004, Ministry of Health and Family Welfare 2004, New Delhi

Some reports found that malaria incidence in PHC Kichha (Nainital, Uttarakhand) and Kharkhoda (Sonepat, Haryana) were much high, 95% (1784 cases) and 97% (7117 cases), higher than reported [76 and 183 cases respectively] in 1983. Similarly in 1985 a group reported 2623 cases as against 49 reported in Gadarpur PHC (Uttarakhand) showing once again a gap of 98%.  In 2010, a report from Haridwar showed that out of the 430 suspected fever patients, 60 were found positive for malaria parasite. 30 % patients were infected by P. falciparum while rest 70 % patients were infected by P. vivax. It was found that about 85% of malarial patients belonged to Below Poverty Line (BPL) and residents of slum area. It indicates that socio-economic conditions (SEC) play a major role in occurrence of this disease. It is also observed in various studies that all parts of India are facing problems related to malaria, except the areas situated at 5000 ft. above sea level. The incidence rate (number of cases per 1000 population) in highest in Arunachal Pradesh followed by Orissa, Mizoram, Goa, Meghalaya, Tripura, Jharkhand, West Bengal, Rajasthan and Chattisgarh (Government of India, 2004). Uttarakhand, the hilly state of India, falls under hypo endemic zone of malaria.

Epidemiology

In India, the epidemiology of malaria is complex because of geo-ecological diversity,      multi-ethnicity, and wide distribution of nine Anopheline vectors transmitting three Plasmodium species mainly: P. falciparum, P. vivax, and P. malariae.  About 80 percent of Indian population lives in low endemic zones with malaria prevalence of less the 2 cases per 1000 population per year. Malaria caused by P. vivax, which is usually less deadly than P. falciparum, is said to account for almost half the reported cases of malaria in the country. However, P. falciparum is usually much more common than vivax. This could be an example of ecological niche partitioning between these species, with one favoured by conditions of low, stable transmission and the other favoured by high transmission (i.e., high mosquito densities and bite rates) and mortality rates.

A map-based approach ‘Malaria Atlas Project’ has been used to estimate the global burden of P. falciparum malaria, which reported the extent of disease caused by P. falciparum in India at about 102 million cases in 2007. In India, P. falciparum infections are particularly high in forested areas inhabited by ethnic tribes in the states of Orissa, Jharkhand, Madhya Pradesh and Chattisgarh.

Types of Malaria

1.      Tribal Malaria: About 44 million populations of tribal areas of Andhra Pradesh, Madhya Pradesh, Chattisgarh, Gujarat, Maharashtra, Bihar, Jharkhand, Rajasthan, Orissa and Northern Eastern states are contributing 50% of P. falciparum cases of country. Infants, young children and pregnant women have been identified as malaria high-risk groups followed by mobile tribal population engaged in forest-related activities. Limited health infrastructure and lack of drugs at village level are the factors responsible for high morbidity and mortality due to malaria.

2.      Rural Malaria: These include irrigated areas of arid and semiarid of Haryana, Western UP, parts of Rajasthan and M.P. These are low endemicity area. An. culcifacies is malaria vector and P. vivax is predominant during lean period and P. falciparum during periodic exacerbation. 

3.      Urban Malaria: 15 major cities including 4 metropolitans accounts for nearly 80% of malaria cases covered under malaria control scheme. This covers about 43.39 million populations. Important features of malaria are moderate to low endemicity with P. vivax predominance and focal P. falciparum transmission. An. culcifacies is the main vector. In peri-urban areas, poor sanitary conditions and low-socio economic groups living in unplanned settlements prone to periodical epidemic influence malaria situation.          

Factors playing role for transmission

The transmission of malaria is determined by climatic, non-climatic and biological factors. The climatic factors include all the independent variables like temperature, rainfall, humidity, etc. while the non climatic factors are human activities, socio-economic conditions like developmental changes, housing and living conditions, adopted control measures, local ecological environment (vegetation, introduction of irrigation schemes) and drug resistance in malaria parasites. Rainfall plays an important role in malaria epidemiology because water not only provides the medium for the aquatic stages of the mosquito’s life but also increases the relative humidity and thereby the longevity of the adult mosquitoes.

Vectors

            Anopheles culicifacies is widely distributed and is the principal vector of rural malaria, An. stephensi is the primary urban vector, An. fluviatilis is a vector in the hills and foothills, and      An. minimus, An. nivipes,  An. philippinensis, and An. dirus are vectors in the northeast and An. sundaicus is restricted to Andaman and Nicobar islands. An. annularis and An. varuna are secondary vectors with wide distribution.

Feeding habits, resting habits, breeding place and biting time

• When high densities build up relatively large numbers feed on men.
• It rests during daytime in human dwellings and cattle sheds.
• Breeds in rainwater pools and puddles, borrow pits, riverbed pools, irrigation channels, seepages, rice fields, wells, pond margins, sluggish streams with sandy margins. Extensive breeding is generally encountered following monsoon rains.
• Biting time of each vector species is determined by its genetic character, but can be readily influenced by environmental conditions. Most of the vectors, including A. 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.

Symptoms

Typical 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 anaemia, 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.

Severe and complicated malaria:

The signs and symptoms are non-specific and may be due to any severe febrile disease (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.

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-malarial 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 programme
• 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 (e.g. Gambusia affinis), bacterium (Bacillus thuringiensis var. israelensis or serotype H14 of B. thuringiensis) in breeding places (ornamental tanks, fountains etc.)
• Use of biocides.

3. Personal Prophylactic 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 bed nets treated with insecticide
• Wearing clothes that cover maximum surface area of the body

4. Community Participation

• Sensitising and involving the community for detection of Anopheles breeding places and their elimination
• NGO schemes involving them in programme strategies

5. Environmental Management & Source Reduction Methods

• Source reduction i.e. filling of the breeding places
• Proper covering of stored water
• Channelization of breeding source
• Monthly Computerized Management Information System (CMIS)
• Field visits by state by State National Programme Officers
• Field visits by Malaria Research Centres and other ICMR Institutes
• Feedback to states on field observations for correction actions.

6. Monitoring and Evaluation of the programme

Preventing and Controlling Malaria other steps:

1. Although surveys over the last 5 years countrywide have consistently found that more than 25% of P. falciparum infections are resistant to chloroquine, this drug has been maintained as first-line treatment.
2. As these have little to offer, except a prick in the finger and some chloroquine tablets, patients increasingly seek the assistance of private providers, whose services are also highly inadequate and not always accessible for poor remote populations.
3. The targeting of indoor residual spraying is based on loose criteria; it is carried out with poor quality and often sabotaged by the population.
4. There has been, therefore, no measurable impact, despite good results in controlled trials in some areas and high population acceptance in many (but not all) rural areas.

Suggestive approach:

For estimate and validate the malaria morbidity:

1)      There is a need of developing a module on malaria morbidity with questionnaire for demographic surveys, almost regularly conducted in India. This module provide malaria incidence on the basis of symptomatology. The symptomatology-based incidence should be converted to the actual number of malaria cases by using a multiplier. This multiplier should be developed by matching results of a sample of symptomatic case with the result of laboratory testing.

2)      A module will be developed based of questions on step-wise lay worker sequential probes so that the symptomatology approach should give estimates of malaria incidence as close to malaria cases as possible. This model already exists from the work of MERG (the monitoring and evaluation reference group) of Roll Back Malaria – it is most suited to Africa but may be adapted for India. Any survey will not capture all positive cases in endemic areas as people are found to be infected with malaria parasites without showing any symptoms. Therefore, it was suggested that this approach should be used only if the approach of examining blood films, for estimating the incidence cannot be implemented. All efforts should be made to estimate incidence of malaria through laboratory diagnosis of blood.

3)      To understand the estimation of malaria morbidity existing data should be subjected to further analysis and research studies, examining the burden of malaria at community level should be reviewed and summarized.

To estimate and validate the malaria mortality:

1)      To developed a simplified protocol on criteria for categorization of deaths attributable to malaria with reviewing passive and active case detection data at Primary Health Centre (PHCs) to estimate malaria in “silent villages”.

2)      Select the hospitals in each of state that report the highest number of deaths and recruiting and training physicians for scrutinizing and synthesizing data with conducting three-day training programme.

3)      Undertaking a household survey which would include parasite prevalence, Insecticide-Treated Nets (ITN) / Indoor residual spray (IRS) utilization, treatment given by public and private sectors.

4)      Pilot studies which link the existing NMEP surveillance with additional questions, verbal autopsy (should be validated by Medical Certification of Cause of Death {MCCD}) instruments for recorded deaths, plus further research on the blood samples collected should be done in partnership with National Malaria Eradication Programme (NMEP) in different sites.

* Corresponding Author:

Dr. Avijit Kumar Awasthi, Ph.D.

Tutor/Demonstrator,

Department of Microbiology,

Government Medical College,

Haldwani, Nanital-263129

Email: akaa21@gmail.com