Investigation of malaria outbreak in Bahraich district, Uttar Pradesh
Dhiman, R C
Background & objectives: Based on the reports of 139 fever related deaths in Jarwal primary health centre (PHC) of Bahraich district, Uttar Pradesh (UP) during April to September 1999, a study was undertaken to explore the possibility of outbreak of Plasmodium falciparum malaria in the area and reasons of outbreak.
Methods: The study was undertaken during September-October 1999 in Bahraich district, UP. The study included a parasitological and an entomological survey. Blood slides from fever cases were collected and examined following standard procedures for detection of species and stage of parasite. The resting adult mosquitoes were collected from human dwellings and cattle sheds from selected villages. Susceptibility status of Anopheles culicifacies to 4 per cent DDT and 0.05 per cent deltamethrin was determined under laboratory conditions following the WHO procedure. In vitro drug sensitivity of P. falciparum to chloroquine was also estimated.
Results: Overall slide positivity rate (SPR) was found to be 33.8 with a preponderance of P. falciparunt (88.4%). There was an outbreak of Pf malaria in Jarwal and surrounding areas as well. Foci of P. falciparum malaria were found in Jarwal, Fakharpur and Hazoorpur PHCs around Kaisarganj PHC. In addition, P. falciparum cases, were also reported from Motipur and Tejwapur.
Interpretation & conclusion: Poor surveillance of affected areas resulting in low annual parasite incidence (API), lack of insecticidal spray in the currently affected PHCs as the API was less than 2 and development of resistance in P. falciparum to chloroquine were found as the possible reasons for the outbreak. It is recommended that surveillance be strengthened in all PHCs of Bahraich district to contain further extension of malaria in northeastern UP.
Key words Anopheles culcifacies – drug resistance – epidemic- malaria – Plasmodium falciparum – surveillance
Bahraich district in Uttar Pradesh (UP) has been considered to have low malariogenic potential based on epidemiological records of National Malaria Eradication Programme (NMEP)1 and malariogenic stratification of Uttar Pradesh based on sibling species2. However, during April to September 1999, 139 fever related deaths were reported in Jarwal primary health centre (PHC) of Bahraich district, UP (as per records of Chief Medical Officer, Bahraich). The epidemiological data of Bahraich district in the past five years indicated that there were only four cases of Plasmodium falciparum (Pf) in 1995 which increased to 33 in 1996, 95 in 1997 and 245 in 1998. In 1999, till September end, a total of 516 cases including 23 cases of Pf were recorded. Annual parasite incidence (API) in any of the primary health centers (PHCs) of the district since 1995 was less than 2 (except Kaisarganj PHC). Kaisarganj PHC alone recorded 84.8 per cent (208 of 245) of the Pf cases of the district in 1998 and deltamethrin was sprayed to contain transmission. In 1999, Pf cases were reported only from Kaisarganj (9), Jarwal (5) and Motipur (8) PHCs and a slide positivity rate (SPR) and Pf per cent in the district was 0.65 and 4.45 respectively.
Jarwal PHC recorded 14, 67, 32 and 83 cases (74 P. vivax, 9 P. falciparum) of malaria in 1995, 1996, 1997 and 1998 respectively while in 1999 there were 177 cases (including 5 cases of Pf) till September 1999. Keeping in view the fever related deaths from Jarwal PHC, an investigation was carried out to explore the possibility of outbreak of P. falciparum malaria, and to find out the reasons.
Material & Methods
Bahraich district is bordered by Nepal in the north, Kheri and Sitapur district of UP in west, Barabanki in south; and districts Gonda and Shrawasti in east. River Ghaghra flows all along the western side of Bahraicli district. Of the 19 PHCs of the district, seven have flood prone areas of Ghaghra river. River Suryu also passes almost longitudinally through the district. The study villages (Haidrabad, Khyalepurva, Pyarepurwa, Belnapara-Hussain) were selected in Jarwal PHC where fever related deaths were reported. Villages of adjoining PHCs viz. Singro (Fakharpur), Bhangha (Hazoorpur), Gudhaiya I (Kaisarganj) and Basheri (Ahwa Hussain Pur) were also selected to delimit the area of outbreak. The parasitological survey of all fever cases (with history of fever in past 8 wk) was carried out from 26th September to 3rd October 1999. Sample blood survey among children (age group 8-12 yr) of a primary school in Haidrabad village (randomly screened from children of 3rd and 4th classes) was also carried out to find the impact of control operations undertaken by the state government. Blood smears collected in field were examined there itself and radical treatment was given (if not given earlier) as per the National Anti Malaria Programme (NAMP) drug policy3. The species and stages of malaria parasites were recorded in each malaria positive case. The age groups and sex of malaria positive subjects were also analysed. A total of 2-3 ml of venous blood from P. falciparum positive cases was drawn after confirming healthy asexual stage of parasites in blood smear. The samples were transported to Malaria Research Centre (MRC), Delhi (after preserving in sorbitol-glycerin cryopreservative) in liquid nitrogen. The samples were revived and cultivated in vitro and the in vitro drug sensitivity test was performed after synchronizing the culture to ring stage parasites4-7. Entomological survey was carried out for the presence of adult malaria vector species in human dwellings and cattle sheds as per the WHO manuals. Insecticide susceptibility status of Anopheles culicifacies to DDT and deltamethrin was determined9.
Analysis of available epidemiological data: The epidemiological data were collected from the Office of Deputy Chief Medical Officer (DCMO) (Malaria and communicable diseases), Bahraich. The current epidemiological data of Bahraich district for the year 1999 (till September) indicate that overall slide positivity rate (SPR) in Bahraich district was 0.65 and slide falciparum rate (SfR) was 0.02. PHC-wise incidence of malaria in the last five years reflected no outbreak of malaria except an increase in P. vivax cases in Jarwal PHC.
The reports of fever related deaths in Devidaspur (Haidrabad village) and Gandara subcentres of Jarwal PHC since April 1999, attracted the attention of health authorities resulting in strengthening of surveillance, extensive radical treatment for fever and indoor residual spray by deltamethrin in most of the affected villages under close supervision.
Subcentre wise break up of 139 fever related deaths was: Haidrabad-60; Belnapara-38; Birahimpur-23; Nimdipur-7, Susi -6; Gandara (Khyalepurva)-5 and monthly distribution from April to September 1999 was 1, 10, 11, 22, 79 and 16 respectively. The age-wise analysis of fever related deaths revealed that 57.5 per cent of deaths occurred in the age group of > 25 yr while the age groups of
Parasitological findings: The results of parasitological survey of all fever cases for detection of malaria parasites are given in Table I. Results indicate that of the 307 blood smears collected from individuals with fever/history of fever, 104 were positive for malaria parasites and the overall SPR and SfR were 33.8 and 29.9 respectively. A preponderance of P. falciparum parasite, i.e., 88.4 per cent (92 of 104) of total malaria cases was seen.
In Haidrabad village (Jarwal PHC) SPR was 71.8. In a sample blood survey conducted in 50 children of a primary school of Haidrabad village, SPR was 10. In village Khyalepurwa of Gandara subcentre, Jarwal PHC, SPR was 52.6 and SfR 45.6.
In order to find the focus of outbreak, parasitological survey was also carried out in Fakharpur, Hazoorpur and Ahwa Hussain Pur PHCs from where no case of P. falciparum malaria was reported till September 1999 (as per DCMO records). The situation of malaria was found alarming in Singro village of Fakharpur (SPR 51.5 and SfR as 48.4) and Bhangha village, Hazoorpur PHC (SPR and SfR as 25 and 18.1 respectively).
The age groups of malaria positive persons (104) was: 25 yr : 41(39.4%). The youngest child affected by malaria was one year old. Sex ratio (male : female) of malaria positive individuals was 1.08:1. Ring stage of P. falciparum parasite was found in 90 per cent (83 of 92) of positive slides.
Entomological findings: Indoor resting collections in human dwellings and cattle sheds revealed the presence of A. culicifacies, A. annularis, A. aconitus, A. pallidus, and A. subpictus. The man hour density (MHD) of A. culicifacies, the known vector of malaria in this area ranged from 1.0 to 3.5 in malaria affected villages. In Haidrabad village, not a single mosquito was collected. On the other hand, MHD of A. culicifacies was 17.2 in an unaffected village Soharwa (Chittaura PHC) where no spray of insecticide was done (Table II).
Susceptibility of vectors to insecticides: A. culicifacies collected from Soharwa village of Chittaura PHC were found resistant to DDT (only 7.33% mortality with one hour exposure of 3 replicates of 20 mosquitoes each to 4% DDT) but fully susceptible (100% mortality in 15 min only) to 0.05 per cent deltamethrin. Due to very low density of A. culicifacies in malaria affected sprayed areas, susceptibility status of vector to insecticides could not be determined.
Sensitivity of P. falciparum parasite to chloroquine: Twenty-one blood samples selected randomly from 92 Pf positive individuals were tested for in vitro drug sensitivity to chloroquine. The growth of parasite was possible in I samples. Of these 11 samples, six were sensitive and five samples (three from Khyalepurwa, Jarwal PHC and two from Singro village, Fakharpur PHC) were found resistant to chloroquine. Of the five resistant samples, two were resistant up to 64 p mol and three up to 16 p mol.
The results of the present investigation revealed that there was an outbreak of malaria in Jarwal, Fakharpur, and Hazoorpur PHCs of Bahraich district. The finding of 19.23 per cent malaria cases up to the age of 5 yr (minimum age 1 yr) indicated that the transmission was indigenous. The presence of ring stage of parasite in 90 per cent of Pf positive individuals indicated that the transmission was still going on. As there was no microscopic confirmation of fever related deaths, the reason of deaths could not be ascertained. The finding of 10 SPR among school children in Haidrabad village indicated that transmission was still going on in spite of mass radical treatment and indoor residual spray by deltamethrin. It may be due to development of drug resistance in P. falciparum to chloroquine and non compliance of treatment schedule by socioeconomically poor population. The presence of vector species A. culicifacies (though in very low density) from one village sprayed with deltamethrin indicated that the coverage of indoor residual spray was not adequate. It was interesting to note that in Singro village (with no insecticide spray) SPR was 51.5 but A. culicifacies was not encountered. It was learnt that people were using pyrethrum knock down spray to get protection from mosquito bites.
The significant factors which led to increase in Pf cases were (i) poor surveillance in the affected areas while already established focus of malaria was present in the vicinity (Kaisarganj); (ii) owing to reporting of less than 2 API, there was no spray of residual insecticide in the affected areas of Jarwal, Fakharpur and Hazoorpur PHCs since 1995; (iii) development of resistance in Pf to chloroquine which further disseminated the resistant parasite; and (iv) lack of staff and expertise in detection of malaria parasites in blood smears (88.4% incidence of Pf in the present findings as compared to reported 4.45% till September 1999; Source of data : Office of DCMO, Bahraich).
Based on present findings and earlier records, the foci of Pf malaria in Bahraich district may be delimited to Jarwal, Fakharpur, Hazoorpur, Kaisarganj, Tejwapur and Motipur along the rivers Ghaghra and Saryu. It is noteworthy that an embankment along the river Ghaghra was built in 1982. The focus of Pf malaria seems to have established slowly in this area under Kaisarganj PHC and now affecting the adjoining PHCs. It needs to be investigated further.
The occurrence of outbreak of malaria from Bahraich district of Uttar Pradesh is significant since this area was considered non-epidemic and species B of A. culicifacies complex, a poor/non-vector of malaria, has been recorded from this area2. Lack of detection of malaria cases, poor surveillance and lack of spray of residual insecticides, development of insecticide resistance in vector species have been found to be common in Uttar Pradesh and many other parts of the country10,11. The rising prevalence of Pf in this eastern district of Uttar Pradesh and detection of resistance to chloroquine is a matter of concern. It is, therefore, suggested that surveillance be strengthened in all PHCs, local technical staff should be trained for laboratory diagnosis of malaria, synthetic pyrethroid insecticides for vector control (or malathion, if vector is not found resistant) be used and treatment regimen for chloroquine resistant cases be implemented as per NAMP drug policy1,3.
The authors thank Shriyut Pritam Singh and Inder Singh, for technical support, Shriyut Praveen Kumar, Laxman Papola, Umesh Jha and Surendra Kumar of MRC, Delhi for assistance provided in field work. Thanks are also due to Dr B.S. Saluja, Chief Medical Officer (CMO) and Dr A.H. Khan, Deputy CMO, Bahraich for cooperation in field work and providing epidemiological records of malaria.
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R. C. Dhiman, C.R. Pillai & S.K. Subbarao
Malaria Research Centre (ICMR), Delhi, India
Received June 30, 2000
Reprint requests: Dr R.C. Dhiman, Assistant Director, Malaria Research Centre (ICMR), 2 Nanak Enclave Delhi 110009, India
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