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Table of Contents
REVIEW ARTICLE
Year : 2019  |  Volume : 56  |  Issue : 1  |  Page : 46-52

Preparedness for malaria elimination in the wake of climate change in the State of Uttarakhand (India)


1 ICMR-National Institute of Malaria Research, New Delhi, India
2 Field Site, Bhimtal, Nainital, India
3 District Malaria Office, Almora, India
4 State Programme Office, NVBDCP, Dehradun, Uttarkahand, India

Date of Submission26-Mar-2019
Date of Web Publication7-May-2019

Correspondence Address:
Dr Ramesh C Dhiman
ICMR–National Institute of Malaria Research, Sector 8, Dwarka, New Delhi-110 077
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-9062.257774

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  Abstract 

Background & objectives: Climate change is an emerging issue particularly in the context of vector-borne diseases. A study was undertaken in Nainital and Almora districts of Uttarakhand to provide evidences of changing climatic conditions, abundance of vectors, and knocking of malaria in hilly areas.
Material and methods: Longitudinal data on temperature and relative humidity were procured from Tussar Silk Centre, Bhimtal, India as well as generated using HOBO device. Monthly density of malaria vectors, their positivity for sporozoite proteins of malaria parasite and fever surveys were conducted as per the standard procedures from 2010 to 2013. Epidemiological data were procured from the State Programme Officer of Uttarakhand state.
Results: It was found that the temperature has increased since 1990 resulting in extension in windows of malaria transmission, temporal distribution as well as man hour density of Anopheles culicifacies and An. fluviatilis in hilly districts of Uttarakhand state. Both the vectors were found in high density up to a maximum man hour density of 110 (An. culicifacies) and 69 (An. fluviatilis) as compared to 32 and 33, respectively during 1998. The field collected vector species were also found positive for sporozoite proteins of malaria parasites in the month of October and November. Evidence of occurrence of malaria cases was also found in areas hitherto free from malaria.
Interpretation & conclusion: The findings reveal that Himalayan region needs attention to strengthen surveillance for malaria to identify emerging new foci of malaria transmission in view of climate change. Health education to communities about preventive measures to contain breeding of vectors and seeking timely treatment should be imparted so as to achieve the goal of malaria elimination in category-1 in the first instance.

Keywords: Anopheles culicifacies; Anopheles fluviatilis; climate change; Himalayan region; malaria; relative humidity; temperature


How to cite this article:
Dhiman RC, Singh P, Yadav Y, Saraswat S, Kumar G, Singh R K, Ojha V P, Joshi B C, Singh P. Preparedness for malaria elimination in the wake of climate change in the State of Uttarakhand (India). J Vector Borne Dis 2019;56:46-52

How to cite this URL:
Dhiman RC, Singh P, Yadav Y, Saraswat S, Kumar G, Singh R K, Ojha V P, Joshi B C, Singh P. Preparedness for malaria elimination in the wake of climate change in the State of Uttarakhand (India). J Vector Borne Dis [serial online] 2019 [cited 2019 Aug 20];56:46-52. Available from: http://www.jvbd.org/text.asp?2019/56/1/46/257774




  Introduction Top


Malaria is a climate sensitive disease[1] and its distribution in different geographic areas reflects the prevalent temperature, rainfall pattern and relative humidity[2]. At present, there are 99 malaria endemic countries of which 67 are in the phase of malaria control while 32 are heading towards elimination. University of California, San Francisco (USA) launched the Malaria Elimination Initiative (MEI) in 2007, which generated three global documents advocating malaria elimination and eradication (http://www.shrinkingthemalariamap.org/ who-we-are/malaria-elimination-group). This task was further taken over by the World Health Organization (WHO)[3]. As per the Global Malaria Technical Strategy of World Health Organization, more than 25 countries have planned to eliminate malaria by 2025 while more than 35 countries intended to eliminate malaria by 2030. In 2016, the National Vector Borne Disease Control Programme (NVBDCP), Government of India, developed a National Framework for Malaria Elimination in India, 2016–2030[4] and in 2017 developed a National Strategic Plan (2017–2022) (NSP) for malaria elimination[5].

As per NSP, the districts have been categorized into four categories, i.e. category 0, 1, 2, and 3. In category 0, there are 75 districts under prevention of re-establishment phase; under category 1, there are 448 districts, which are in elimination phase; while in category 2 and 3 there are 46 and 109 districts in pre-elimination phase and intensified malaria control activities, respectively. The NSP has identified several researchable issues like ecological changes leading to outbreaks, development of early warning system but unfortunately, climate change issue did not find place. It has been established that climate change is bound to alter the distribution of vector-borne diseases of which malaria ranks at top in terms of morbidity and wide distribution[6],[7],[8]. In India also, several studies have highlighted the impact of climate change on malaria[9],[10]. As per studies undertaken in India, Himalayan region is projected to have new foci of malaria transmission while increased intensity of transmission in northeastern states[11]. In order to generate the evidence of climate change, Nainital and Almora districts located at the fringe area of Himalayan region in Uttarakhand were selected.


  Material & Methods Top


Study area

In the State of Uttarakhand, Almora and Nainital districts were selected for generation of entomological and parasitological data. Nainital district lies at 29.23 °N and 79.30 °E. To its north is Almora district and in south lies the Udham Singh Nagar district. Of three distinct physiographic zones in Nainital district, located at an altitude ranging from 2068 m, the hilly areas are usually considered free from malaria, while Bhabar and Terai zones are endemic for malaria since long[12]. Bhabar zone is characterized by scarcity of water extending from Lalkuan to Kathgodam while Terai zone extends from Kichha to Lalkuan and is characterized by presence of high water table[13]. The District has reported malaria from Terai and Bhabar physiographic zones, while hilly areas were free from malaria till 2001[14]. Anopheles culicifacies and An. fluviatilis (Diptera: Culicidae) have been incriminated as vectors of malaria. Almora district is in the Kumaon division of Uttarakhand state, located at 29.37 °N, 79.37 °E and at altitude of 1638 m above the mean sea level. The town of Almora is surrounded by Pithoragarh district to the east, Garhwal region to the west, Bageshwar district to the north and Nainital district to the south.

Two Primary Health Centres (PHCs), each from hilly and Bhabar zones erstwhile in Nainital district (now in Udham Singh Nagar district) were selected for fever and entomological surveys and analysis of observed and generated data on temperature and relative humidity (RH).

Data on temperature and relative humidity

Data on temperature and RH for the period of 18 years (1990–2008) were procured from the local weather station of Tussar Silk Centre, Bhimtal for determination of Transmission Windows (TW) of malaria in the district[11]. For further refined analysis, data on temperature and RH were generated by installing Onset HOBO data logger (Onset USA) at 4-hourly interval in Bhorsa village.

Entomological surveys

Fortnightly entomological surveys were carried out in identified villages in Bhimtal from 2009–13. The adult mosquitoes were identified using standard keys and man hour density of adult malaria vectors was determined as per the standard procedures[15].

Detection of sporozoites in field collected mosquitoes

A total of 2737 half-gravid female Anopheles mosquitoes were collected and preserved in plastic vials with silica gel. Specimens were screened for species identification using standard keys as mentioned above. Head and thorax parts of An. culicifacies (1737) and An. fluviatilis (1000) were separated and pooled up species-wise up to 5 specimens. Detection of malaria parasites, i.e. P. falciparum or P. vivax was done following the Circumsporozoite-ELISA technique as described by Wirtz et al. (1985 & 1987)[16],[17]. Cut-off Optical Density was taken two times of control above where samples were positive while at lower value, the samples were treated as negative. For detection of P. falciparum, Pf MAb standard reagent, while for P. vivax, Pv 210 and Pv 247 MAb standard reagents were used. The required standard reagents were procured from Centre for Diseases Control and Prevention (CDC), Atlanta, USA.

Fever survey

Blood slides were collected in house-to-house search from persons having fever or with history of fever in last one week. Ethical clearance for undertaking the study and informed consent from subjects was taken on a printed format. Blood by finger pricking was collected with disposable lancets following standard procedure[18]. Thick and thin smears were prepared and stained with JSB-I and II and examined for the presence of malaria parasites microscopically. Radical treatment was given as per the National drug policy for treatment of malaria cases[19].


  Results Top


Observed and generated climatic parameters

Based on the observed temperature data provided by Tussar Silk Centre, Bhimtal, in 1990, six months, i.e. January to March and October to December were not suitable for transmission of malaria. In the year 2008, October month also becomes suitable [Table 1] and [Figure 1]. The gradual increase in temperature from 1990 to 2008 has resulted in increase in one month of transmission. When the TWs were determined using temperature and RH combined, the windows were open for five, six and six months, respectively during 1990, 2008 and 2009–14.
Figure 1: Observed temperature and relative humidity data procured from Tussar Silk Centre, Bhimtal, Nainital.

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Table 1: Transmission windows of malaria in Bhimtal, PHC Nainital (based on T 18–32 °C for open window)

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The data on temperature and RH generated at Bhorsa village revealed that temperature is suitable for eight months of transmission, i.e. from March to October months. When we combined RH with Temperature the windows showed unsuitability during April and May months due to <50% RH [Table 1] and [Figure 2].
Figure 2: Temperature and relative humidity data generated at Bhorsa village, Nainital.

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Entomological surveys: In the villages under Hills in Ramgarh PHC, no adult anopheline was found, though larvae were collected. From Bhimtal PHC, the highest density of An. fluviatilis, a known malaria vector was 69 per man hour from the village Bhorsa [Figure 3]. Highest man hour density (MHD) of An. culicifacies was 110 in the month of August. The availability of An. culicifacies was found for 6–7 months in a year, while An. fluviatilis was found in two peaks, i.e. March to May and September to October.
Figure 3: Man hour density of major vectors of malaria in village Bhorsa, Nainital district.

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In Raikhalkatta village under Motahaldu PHC, the maximum MHD of An. culicifacies was found up to 276 in the month of May 2012 [Figure 4]. Anopheles culicifacies was available from 9–11 months while An. fluviatilis from 7–9 months.
Figure 4: Man hour density of malaria vectors in Raikhalkhatta village, Motahaldu PHC Bhabar zone (Nainital)

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In Jyadi village under Almora district, the availability of An. culicifacies was found from 3–6 months with maximum MHD up to 20 [Figure 5]. Anopheles fluviatilis was found mainly for 2–7 months with maximum MHD of 74 in the month of April 2013.
Figure 5: Man hour density of malaria vectors at Jyadi village, Tarikhet PHC, Almora

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Positivity of field collected malaria vectors to malaria parasite

Anopheles culicifacies and An. fluviatilis collected from field were found positive for antigens of P. vivax and P. falciparum [Table 2]. Anopheles culicifacies were found positive for P. vivax and P. falciparum in the months of May to July. On the other hand, An. fluviatilis were found positive for P. falciparum in the month of June and October, while for P. vivax, in the month of November.
Table 2: Detection of sporozoites from field collected anophelines from Nainital and Almora districts (Uttarakhand)

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Fever survey: The results of fever survey undertaken in hilly areas of Almora and Nainital districts are given in [Table 3]. The findings revealed that in Bhorsa, Nishola and Mirchijhala villages under Bhimtal PHC, P. vivax and P. falciparum cases were detected. Maximum cases (7) were detected in Bhorsa village, of which three were P. vivax and 4 P. falciparum. In Almora district, mainly P. falciparum cases were detected during 2010–2012 in March, May and August months.
Table 3: Fever survey undertaken in Nainital and Almora districts from 2010 to 2013

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A total of 522 blood slides were prepared from fever cases from 14 villages of five PHCs during the surveys [Table 3]. Of 117 blood slides collected from five villages under Bhimtal PHC, five P. falciparum and four P. vivax cases were detected from Bhorsa, Mirchijhala and Nishola villages with maximum slide positivity rate (SPR) up to 14.2. The age group and stage of malaria parasites of nine positive cases was: Male (M) aged 21 yr with P. falciparum ring stage from Nishola; M63 with P. vivax gametocytes from Mirchijhala; and M17 with P. falciparum ring stage, Female (F) 16 with P. falciparum ring stage; M20 with P. vivax gametocyte; F16 with P. falciparum ring and gametocytes; F17 with P. vivax trophozoites and F5 with P. vivax gametocytes and P. falciparum (ring stage) M 2.5 from Bhorsa. Personal interrogation of positive malaria cases from these villages, revealed that except one male aged 21 years (from Nishola village who works at Haridwar), rest of the 8 positive cases did not travel out of their native villages in the last two years. Bhorsa and Mirchijhala villages are about 7 km away from Amia village, and are at the altitude of 649 and 783 m above the mean sea level. Nishola village, which recorded one case of P. falciparum, is at an altitude of 1227 m. From Almora district, one P. vivax and nine P. falciparum cases were detected mainly from Jyadi and Chapad villages under Tarikhet PHC. The mapping of district-wise occurrence of malaria cases from 2010 to 2018 in the State of Uttarakhand is shown in [Figure 6].
Figure 6: District wise reported malaria cases in the state of Uttarakhand from 2006 to 2018 (Source: SPO Office, Dehradun).

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  Discussion Top


Altitude and malaria are related with each other as the temperature decreases with increase in altitude[20],[21]. As per the available literature, malaria has been found prevalent sometimes at 5000 ft altitude in the Himalayas and at still higher levels (6000–7000 ft) in South India, however, they are neither frequent nor severe in character and their origin is not certain. In Nainital district, malaria has been reported till Amia village near Kathgodam which is at the altitude of 614 m.

The findings of the present study revealed that cases of malaria were found beyond Kathgodam, i.e. in Bhorsa village at an altitude of 578 m and has started penetrating up to 1227 m (Nishola village,1227 m). It is to point out here that as per the records of District Malaria Office, Nainital, the whole district of Nainital reported only 3 cases of P. falciparum from 1998 to 2007. During the present survey, the reason of occurrence of malaria cases (4 P. vivax and 4 P. falciparum) in Bhorsa and Mirchijhala villages under hilly area of Bhimtal PHC may be attributed to increased temperatures.

Areas at higher altitude beyond Bhimtal were found free from malaria. Temperatures are favourable for transmission of malaria for some months even in hilly areas like Mukteshwar located at 2307 m height, but there is no record of malaria so far. It may be explained by the fact that for indigenous transmission of malaria, a buildup in density of anopheline vector is required.

The analysis of temperature from 1990 to 2008 indicated that increase in temperature in March and October months has opened the extra windows of transmission in Bhimtal. Further, from 2009–14, the rise in temperature has been observed in the months of March and October months at village-level. On the other hand, during winter months particularly January and February months, reduction in temperature has also been observed in 2008 as compared to 1990.

Another major finding of the study is the increase in temporal distribution of malaria vectors, increase in MHD and positivity of vectors for malaria sporozoite proteins during October and November months in Almora and during May and June in Nainital districts. Results of survey undertaken in 1998–99 for anopheline density in three different physiographic zones of Nainital district[13] clearly indicated that An. culicifacies was found only in the month of August in hills, two months in Bhabar zone and four months in Terai and the highest density was 32 in hilly zone only in the month of August 1998 as compared to 110 (An. culicifacies) in the month of August 2013 in the present study. The highest density of An. fluviatilis in Bhorsa village (hilly area) was found to be 69 as compared to 33 reported from hilly areas earlier. In Almora district also, maximum MHD of An. culicifacies has been found to be 20 in the month of June 2012 while MHD of An. fluviatilis was found up to 74 in the month of May 2013.

The overall findings of the study highlight that due to increase in temperature the window of malaria transmission has expanded and P. falciparum, which was already at the threshold of hilly areas up to Kathgodam has extended further deep into the new hilly areas at higher altitudes, which may be attributed to rise in temperatures due to climate change. Increase in temporal distribution and MHD of malaria vectors further provide the evidence that conditions are quite suitable for indigenous transmission of malaria in hilly areas of Nainital and Almora districts of Uttarakhand which were hitherto free from malaria. It is to mention here that Almora, Pithoragarh and Uttarkashi districts which were considered free from malaria have started reporting malaria cases from 2010 onwards [Figure 6].

Craig et al[22] determined a minimum of three consecutive months for suitability of malaria transmission in Africa. Cut-off of malaria transmission due to RH is not understood clearly that is why in the month of April, P. falciparum cases were detected from Bhimtal PHC, when RH was 36.32% [Table 1]. When the TWs are determined based on temperature alone and with T+RH combined, there is reduction in April and May months due to decrease in RH [Table 1]. The availability of malaria vectors, positivity of field collected mosquitoes for malaria sporozoite proteins and positivity of patients in the month of May suggest that transmission does not stop due to < 50–55% RH (44.7–45.2%). In a study undertaken in Jodhpur (Rajasthan) during the month of May–June, Batra et al[23] reported malaria cases when the temperature was above 40 °C. It suggests that mosquitoes find micro niche for resting in houses to meet the condition of required temperature and RH which are quite different from outdoor climatic conditions. It warrants to elucidate the role of outdoor or indoor RH for determining transmission windows of malaria or any other vector-borne diseases.


  Conclusion Top


As per the malaria elimination goal by the National Programme (http://www.searo.who.int/india/publications/national_framework_malaria_elimination_ india_2016_2030.pdf), Nainital and Almora districts are in category-1. The present findings warrant intensive surveillance and constant vigil in fringe areas of malaria endemic areas in Himalayan region so that the foci of transmission are also eliminated before further spread in hitherto malaria-free areas in Himalayan region. It is high time to initiate assessment of adaptation measures in vulnerable areas to nip the evil in the bud.


  Acknowledgements Top


We acknowledge the Indian Council of Medical Research for funding the project under Global Environmental Change and Health initiative. Thanks are also due to the State Programme Officer, Uttarakhand and District Malaria Officers of study districts for support in sharing epidemiological data of malaria. Technical assistance provided by Messrs M.C. Sharma, Umesh Jha, V.P. Singh, Bharat Singh, Surendra Kumar, Santosh Bhui, and Keshava Rao is duly acknowledged.



 
  References Top

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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