Preparedness of primary & secondary care health facilities for the management of non-communicable diseases in tribal population across 12 districts in India

Background and objectives: Non-communicable diseases (NCDs) are highly prevalent in the tribal populations; however, there are limited data regarding health system preparedness to tackle NCDs among these populations. We estimated the availability of human resources, equipment, drugs, services and knowledge of doctors for NCD management in the selected tribal districts in India. Methods: A cross-sectional survey was conducted in 12 districts (one from each State) with at least 50 per cent tribal population in Andaman and Nicobar Islands, Himachal Pradesh, Madhya Pradesh, Odisha and eight northeastern States. Primary health centres (PHCs), community health centres (CHCs) and district/sub-district hospitals (DHs) were surveyed and data on screening and treatment services, human resources, equipment, drugs and information systems indicators were collected and analysed. The data were presented as proportions.Results: In the present study 177 facilities were surveyed, including 156 PHCs/CHCs and 21 DHs. DHs and the majority (82-96%) of the PHCs/CHCs provided outpatient treatment for diabetes and hypertension. Overall, 97 per cent of PHCs/CHCs had doctors, and 78 per cent had staff nurses. The availability of digital blood pressure monitors ranged from 35 to 43 per cent, and drugs were either not available or inadequate. Among 213 doctors, three-fourths knew the correct criteria for hypertension diagnosis, and a few correctly reported diabetes diagnosis criteria. Interpretation & conclusions: The results of this study suggest that the health system of the studied tribal districts was not adequately prepared to manage NCDs. The key challenges included inadequately trained workforce and a lack of equipment and drugs. It is suggested that capacity building and, procurement and distribution of equipment, drugs and information systems to track NCD patients should be the key focus areas of national programmes

Non-communicable diseases as a major contributor to deaths in 12 tribal districts in India

Background & objectives: Non-communicable diseases (NCDs) are the leading cause of death in India. Although studies have reported a high prevalence of NCD in tribal populations, there are limited data pertaining mortality due to NCDs. Therefore, in this study we estimated the proportion of deaths due to NCDs among 15 yr and older age group in tribal districts in India. Methods: We conducted a community-based survey in 12 districts (one per State) with more than 50 per cent tribal population. Data were collected using a verbal autopsy tool from the family member of the deceased. The estimated sample size was 452 deaths per district. We obtained the list of deaths for the reference period of one year and updated it during the survey. The cause of death was assigned using the International Classification of Diseases-10 classification and analyzed the proportions of causes of death. The age-standardized death rate (ASRD) was also estimated. Results: We surveyed 5292 deaths among those above 15 years of age. Overall, NCDs accounted for 66 per cent of the deaths, followed by infectious diseases (15%) and injuries (11%). Cardiovascular diseases were the leading cause of death in 10 of the 12 sites. In East Garo Hills (18%) and Lunglei (26%), neoplasms were the leading cause of death. ASRD due to NCD ranged from 426 in Kinnaur to 756 per 100,000 in East Garo Hills. Interpretation & conclusions: The findings of this community-based survey suggested that NCDs were the leading cause of death among the tribal populations in India. It is hence suggested that control of NCDs should be one of the public health priorities for tribal districts in India.

Characterization of the anopheline vector breeding habitats: Implications for elimination of malaria in tribal inhabited Car Nicobar Island

Background & objectives: Malaria is an important public health problem in Andaman & Nicobar archipelago. Among the three districts, Nicobar is the most endemic district where API is >2. In this district, the malaria incidence in Car Nicobar Tehsil has declined steadily over the past 10 years. A renewed initiative to consolidate this gain is being made with the ultimate objective of achieving zero indigenous transmission of malaria in Car Nicobar. So, the present study undertook a close environmental monitoring of water bodies for assessing changes in the risk potential of mosquito vector breeding habitats which can augment the elimination programme. Methods: The breeding habitats of anopheline mosquitoes were sampled in 16 areas of Car Nicobar Island for eight time periods during 2017-2020. Along with anophelines, various associated water parameters (n=60) were estimated, viz. physicochemical (n=13), and biological, which included culicine mosquito immatures, insect predators (n=5), phytoplanktons (n=31) and zooplanktons (n=10). Results: In the 16 study sites, overall 1126 surface water stagnating bodies constituting 21 different habitat types were surveyed. Of these, 17 were positive for anopheline breeding. Water bodies from three villages were consistently found to be positive for anopheline breeding. However, early instars of anopheline larvae were more abundant compared to the late instars. Four anopheline species were recorded, including Anopheles sundaicus, A. barbirostris, A. insulaeflorum and A. subpictus, in which 48 per cent were A. sundaicus. Multivariable analysis indicated that anopheline density was significantly higher in permanent water bodies than in temporary habitats (P<0.05) (high risk of anophelines). The highest pH (?8.2), dissolved solids (?0.39) levels showed significantly (P<0.05) decreased larval densities (lower risk of breeding), adjusted with breeding sites and season. Nitrite levels increased (P=0.022) larval densities. Interpretation & conclusions: The present study facilitated estimating the productive period of a larval habitat enabling target larval sources to reduce adult populations. Implementing larviciding strategy before monsoon season is presumably the most cost-effective strategy. The output can be utilized for environmental monitoring of mosquito breeding risk in other malaria endemic areas, particularly where medium/large water bodies are the predominant breeding sites for malaria vectors.

Geographical distribution of primary & secondary dengue cases in India – 2017: A cross-sectional multicentric study

Background & objectives: Dengue virus infection is endemic in India with all the four serotypes of dengue virus in circulation. This study was aimed to determine the geographic distribution of the primary and secondary dengue cases in India. Methods: A multicentre cross-sectional study was conducted at Department of Health Research / Indian Council of Medical Research (DHR)/(ICMR) viral research and diagnostic laboratories (VRDLs) and selected ICMR institutes located in India. Only laboratory-confirmed dengue cases with date of onset of illness less than or equal to seven days were included between September and October 2017. Dengue NS1 antigen ELISA and anti-dengue IgM capture ELISA were used to diagnose dengue cases while anti-dengue IgG capture ELISA was used for identifying the secondary dengue cases. Results: Of the 1372 dengue cases, 897 (65%) were classified as primary dengue and 475 (35%) as secondary dengue cases. However, the proportion varied widely geographically, with Theni, Tamil Nadu; Tirupati, Andhra Pradesh and Udupi-Manipal, Karnataka reporting more than 65 per cent secondary dengue cases while Srinagar, Jammu and Kashmir reporting as low as 10 per cent of the same. The median age of primary dengue cases was 25 yr [interquartile range (IQR 17-35] while that of secondary dengue cases was 23 yr (IQR 13.5-34). Secondary dengue was around 50 per cent among the children belonging to the age group 6-10 yr while it ranged between 20-43 per cent among other age groups. Interpretation & conclusions: Our findings showed a wide geographical variation in the distribution of primary and secondary dengue cases in India. It would prove beneficial to include primary and secondary dengue differentiation protocol in the national dengue surveillance programme.

Leptospirosis among the self-supporting convicts of Andaman Island during the 1920s - the first report on pulmonary haemorrhage in leptospirosis.

Several researchers had carried out investigations on the possibility of existence of Weil’s disease in Andaman Islands during early 20th century. The first report of a series of confirmed cases of leptospirosis that occurred during1929 was published in 1931.There were several reports during 1995 to 2009 that described detailed account of leptospirosis including various clinical syndromes. The possibility of pulmonary involvement in leptospirosis being a manifestation historically overlooked rather than newly emerged during the past two decades is examined in this review in the context of Andaman Islands. Two case series of leptospirosis, one occurred in 1929 and the other in 1996-1997 were reviewed with special emphasis on pulmonary involvement and haemorrhagic manifestations. The similarities and differences in the clinical profile of patients of the two case series were analysed. The review shows that respiratory system involvement and pulmonary haemorrhage as evidenced by presence of haemoptysis as a complication of leptospirosis was occurring during 1920s in Andaman Islands. The incidence of pulmonary involvement, however, rose from 9.4 per cent during 1929 to 52 per cent in 1996-1997. The case fatality ratio in patients with pulmonary involvement, which was 50 per cent during 1929 and 42.9 per cent during 1996-1997, was higher than that in cases without pulmonary involvement.Fever, conjunctival congestion, jaundice, vomiting, diarrhoea, hepatomagaly, haemoptysis, haematemesis and subconjunctival haemorrhage were common in both series. The case series in Andaman Islands in 1929 was probably the first report of pulmonary haemorrhage as a manifestation of leptospirosis. The increase in the incidence of pulmonary involvement in leptospirosis in the recent past is probably due to the increase in the density and diversityof its animal vectors,the broadening of the range of circulating serovars and the interactions between the vector and the agent. An increased virulence of Leptospira through gene acquisition and loss on an evolutionary time scale and the resulting change in the gene content, gene order and gene expression cannot be ruled out.

Herbal medicine & healthcare practices among Nicobarese of Nancowry group of Islands - an indigenous tribe of Andaman & Nicobar Islands.

Background & objectives: Tribal people often depend on herbal medicines and the traditional knowledge practitioners (TKPs) serve as their healthcare service providers. This study was an attempt to document the use of medicinal plants by the Nicobarese of Nancowry group of Islands. Methods: Field survey was conducted in all the five inhabited Islands of the Nancowry group of Islands. All the TKPs were interviewed with a questionnaire-guided ethnomedicinal survey protocol. Voucher specimens of all the cited plants (botanic species) were collected and a community biodiversity register of Nicobarese of Nancowry was prepared. Results: A total of 77 TKPs were identified, who together were using 132 medicinal plant species belonging to 113 genera and 62 families. The TKPs were treating a total of 43 ailments. Seven endemic and three rare plant species were recorded. The most common plant part used was leaves. Remedies were usually prepared using water as the excipient. Routes for administration of medicinal plant preparations were oral, topical and others. The information collected from the TKPs were collated in the form of Community Biodiversity Registers. Interpretation & conclusions: The present survey shows that the medicinal plants play a pivotal role in the healthcare of the Nicobarese tribe of Nancowry group of Islands. Efforts to document the medicinal plant species and the formulations used by them are necessary to prevent the loss of this precious knowledge.

Diurnally subperiodic filariasis among the Nicobarese of Nicobar district - epidemiology, vector dynamics & prospects of elimination.

In India diurnally subperiodic filariasis (DspWB) is prevalent only in the Nicobar district of Andaman and Nicobar Islands. Studies undertaken at different points of time indicate that this form of filariasis is restricted to a small region in Nancowry group of islands where it is transmitted by mosquito Downsiomyia nivea, a day biting mosquito. Studies on prevalence, distribution, and assessment of endemicity status, vector incrimination, bioecology, host seeking behaviour, population dynamics of the vector, transmission dynamics and clinical epidemiology indicate the prevalence and persistence of this infection in the Nancowry group of islands with perennial transmission. There was no control programme in these islands, until the National programme to eliminate filariasis was launched in 2004. Eight rounds of annual mass drug administration (MDA) with diethyl carbamazine (DEC) + albendazole have been completed. Despite this, microfilaria prevalence remains at above one per cent, the level identified for initiating transmission assessment survey to decide on continuation of MDA further. This necessitates adjunct measures to the ongoing MDA programme in these islands. The vector control options could be an adjunct measure, but the vector is a forest dweller with a unique bio-ecology, therefore, not a technically feasible option. Use of DEC fortified salt for six months to one year could hasten the process of elimination. Although administration of DEC-fortified salt is simple, rapid, safe, and cost-effective, challenges are to be tackled for evolving operationally realistic strategy. Such a strategy requires commitment of all sections of the society, a distribution mechanism that ensures the use of DEC-fortified salt in the Nancowry islands. Here we discuss the plan of action to serve the indigenous communities and operationalizing DEC fortified salt strategy through an inter-sectoral approach involving multiple stakeholders.

Emergence of influenza A (H1N1) PDM09 in the remote Islands of India - A molecular approach.

Background: A disease outbreak of A (H1N1) PDM09 was reported in Andaman and Nicobar islands in 2009 with an attack rate of 33.5% among settler population and 26.3% among the aboriginal Nicobarese tribe. During the ongoing outbreak of A (H1N1) PDM09 disease in different parts of the world, a subject working in Dubai city of Saudi Arabia, came to Port Blair, following which the pandemic triggered for the fi rst time in these Islands. Materials and Methods: During the period August 2009 to January 2011, 30 confi rmed cases of Infl uenza A (H1N1) PDM09 virus infection was detected. To understand the genetic relationship, the NA gene sequences of the viruses were phylogenetically analysed together along with the virus sequence isolated from other parts of the world. Result: Formation of multiple clusters were observed, with the sequences of Andaman Islands, mainland India, Mexico, Saudi Arabia and few other counties clustering together. The sequence analysis data revealed that there was no specifi c mutation conferring resistance to oseltamivir among the Andaman A (H1N1) PDM09 virus isolates. The result of phylogenetic analysis have also revealed that the A (H1N1) PDM09 virus might have spread in these remote Islands of India via the subject from Saudi Arabia/Dubai. Conclusion: A (H1N1) PDM09 Infl uenza outbreak have highlighted the need to strengthen the region-specifi c pandemic preparedness plans and surveillance strategies.

Risk factors associated with leptospirosis during an outbreak in Middle Andaman, India.

Background & objectives: Leptospirosis outbreaks occur frequently in North and South Andaman Islands but not in Middle Andaman. In 2002, an outbreak appeared in Middle Andaman for the first time. Although a study on risk factors was conducted in North Andaman, it used seropositivity to define leptospirosis. Since seropositivity might not indicate current leptospiral infection and as no study on risk factors was conducted in Middle Andaman, we carried out this study to identify the risk factors during the outbreak. Methods: A suspected outbreak of leptospirosis occurred in Rangat of Middle Andaman during October - November 2002. Suspected cases were screened for leptospirosis using microscopic agglutination test (MAT). Fifty two patients confirmed to have leptospirosis based on rising titres in MAT on paired sera, and 104 age, sex and neighbourhood seronegative matched controls, were included in the study. A conditional multiple regression by backward elimination process was carried out with acute leptospirosis as the dependent factor and various environmental, occupational and behavioural factors as independent factors. A stratified analysis was also carried out. Results: The presence of cattle in the house, drinking stream water, contact with garbage, walking barefoot and standing in water while working were identified as significant factors associated with leptospirosis. Stratified analysis showed a dose response relationship between number of cattle in the house and the risk of leptospiral infection suugesting that cattle could be a source of infection. Interpretation & conclusions: Identification of the potential risk factors would help understand the transmission dynamics of the disease and formulate public health interventions.

Community-centred approach for the control of Aedes spp. in a peri-urban zone in the Andaman and Nicobar Islands using temephos.

Background. Chikungunya fever struck the Andaman and Nicobar Islands in July 2006. From the entomological point of view, dengue and chikungunya are hard to control due to the high prevalence of Aedes aegypti in both urban and rural areas. Mobilizing communities for the control of Aedes aegypti has not been attempted in India. Methods. We did a prospective observational feasibility study in one peri-urban locality (Brookshabad) to assess the Aedes spp. infestation and subsequently test the efficacy of a community-based approach to control Aedes aegypti. An Aedes infestation larval survey was done with the assistance of community volunteers using the single larval survey (SLS) technique. House index, container index and Breteau index reflecting the relative prevalence and infestation levels were estimated. Various information, education and communication (IEC) campaign tools were developed to disseminate information about the prevalent situation. Several talks were organized to sensitize and motivate the people to realize the problem and participate in solving it. A two-pronged strategy, viz. environmental management through source reduction and anti-larval campaign using temephos was adopted to combat Aedes infestation through community involvement. Results. A total of 533 water-holding containers were searched for Aedes larvae, both indoors (188/533, 35.3%) and outdoors (345/533, 64.7%) from 104 (104/235, 44.3%) premises. Of these, 109 containers (95% CI 17.19%–24.03%) were found to support Aedes spp. larval breeding (20.45%). The Breteau index was 104.8%. Aedes aegypti predominated followed by Aedes albopictus. The most abundant water-holding containers supporting Aedes breeding were plastic, metal drums and cement tanks. These waterholding containers were targeted for temephos application by the community volunteers. Forty rounds of temephos applications were carried out during the study period. The number of containers supporting Aedes aegypti breeding reduced significantly within 1 month post-intervention by community volunteers. As a result the Breteau and house indices dropped from 104.8% to 2.7% and 44.23% to 2.6%, respectively. Thereafter, the indices remained at zero level till completion of the study. Conclusion. Larval indices indicate that Aedes aegypti is well established in peri-urban Brookshabad. Predominance of this mosquito species indicates infiltration into the peri-urban locality and beginning of displacement of Aedes albopictus. Epidemiologically, 3 categories of water-holding containers, viz. plastic, metal drums and cement tanks facilitate breeding of Aedes aegypti. Consequently, targeted source reduction as one way of selectively attacking the most important types of containers with temephos is feasible. Community involvement and networking with the residents allowed for a communitycentred approach to combat Aedes aegypti infestation. As an outcome of this approach, the larval indices reduced significantly and remained low. We suggest that a control strategy emphasizing the use of temephos through a community-centred approach should be considered for these islands. However, close monitoring of this approach is warranted for long term sustainability

Leptospirosis: an emerging global public health problem.

Leptospirosis has been recognized as an emerging global public health problem because of its increasing incidence in both developing and developed countries.A number of leptospirosis outbreaks have occurred in the past few years in various places such as Nicaragua, Brazil and India.Some of these resulted due to natural calamities such as cyclone and floods. It is a direct zoonotic disease caused by spirochetes belonging to different pathogenic species of the genus Leptospira. Large number of animals acts as carriers or vectors.Human infection results from accidental contact with carrier animals or environment contaminated with leptospires. The primary source of leptospires is the excretor animal, from whose renal tubules leptospires are excreted into the environment with the animal urine. Majority of leptospiral infections are either sub clinical or result in very mild illness and recover without any complications.However,a small proportion develops various complications due to involvement of multiple organ systems. In such patients, the clinical presentation depends upon the predominant organs involved and the case fatality ratio could be about 40% or more. Febrile illness with icterus, splenomegaly and nephritis (known as Weil's disease), acute febrile illness with severe muscle pain,febrile illness with pulmonary haemorrhages in the form of haemoptysis, jaundice with pulmonary haemorrhages, jaundice with heamaturea, meningitis with haemorrhages including sub conjunctival haemorrhage or febrile illness with cardiac arrhythmias with or without haemorrhages are some of the syndromes. Because of the protean manifestations of leptospirosis it is often misdiagnosed and under-reported. Although the basic principles of prevention such as source reduction,environmental sanitation, more hygienic work-related and personal practices etc., are same everywhere, there is no universal control method applicable to all epidemiological settings. Comprehensive understanding of the eco-epidemiological and cultural characteristics of a community that faces the problem of leptospirosis is an essential prerequisite for evolving an effective and acceptable control measure.

Phenotypic & genotypic conservation of ompL1 & lipL41 among leptospiral isolates of Andaman Islands.

BACKGROUND & OBJECTIVES: The leptospiral antigens that are conserved among the diverse pathogenic leptospires have potential importance in the development of new serodiagnostic and immunoprotective strategies. The present study was therefore carried out to find out the phenotypic conservation of the leptospiral proteins OmpL1 and LipL41, and the genetic conservation of ompL1 and lipL41 genes among the leptospiral isolates of Andaman Islands and among the reference strains. METHODS: In one dimensional SDS-PAGE the leptospiral samples prepared from strains of various leptospiral serovars were run and transferred on to nitrocellulose paper and probed with pooled convalescent phase human sera to find out the phenotypic conservation of the protein fragments at 31 and 41 kDa. Further, the proteins were indirectly confirmed as OmpL1 and LipL41 by using specific rabbit hyperimmune sera. Specific primers were utilized to amplify the fragments to study the genetic conservation of ompL1 and lipL41. Further, these two fragments were sequenced and BLAST analysis was done with the whole genome of Leptospira interrogans serovar Lai for comparison. RESULTS: Analysis of individual immunoblots using patient sera showed that the OmpL1 and LipL41 were conserved among all the isolates used in the study. Further, these two proteins were probed with specific rabbit hyperimmune sera of OmpL1 and LipL41 for confirming the fragments and it was found to be conserved among all the isolates. The PCR based amplification further showed that the genes ompL1 and lipL41 were conserved among the leptospiral isolates studied. Sequencing followed by BLAST analysis of these showed 97 per cent similarity with the whole genome sequence and low score values in comparison with other bacterial species. INTERPRETATION & CONCLUSION: The antigenic and genetic conservation of the two proteins, OmpL1 and LipL41, indicated that these could be potential candidates for development of diagnostic test systems for leptospirosis.

Comparison of immunoreactive proteins of commonly circulating serogroups of Leptospira in Andaman Islands, India.

BACKGROUND & OBJECTIVE: Early diagnosis is the key to the treatment of leptospirosis. For development of rapid diagnostic kits, a thorough knowledge about the nature of the proteins expressed by the pathogen during infection is necessary. The present study was undertaken to understand the nature of immunoreactive proteins from commonly circulating serogroups of Leptospira in the endemic Andaman and Nicobar Islands, India. METHODS: Proteins were extracted from six strains of Leptospira representing five different serogroups following four different preparation methods, viz., whole cell lysis by sonication, detergent solubilization, outer and inner membrane isolations, and were subsequently characterized on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoblots were made from the sonicated proteins using hyperimmune rabbit antisera, homologous and heterologous patient sera separately. RESULTS: The 67, 65, 45, 43, 35, 32 and 18 kDa major proteins in the whole cell lysate were common among all the five serogroups of Leptospira. The 67, 41, 35, 32, 28 and 22 kDa were the major outer membrane proteins, while 94, 32, 25 and 18 kDa protein were in inner membrane. Immunoblots with hyperimmune rabbit antisera detected 67, 65, 60, 45, 43, 41 and 32 kDa common proteins from the whole cell lysates of all strains while homologous and heterologous patient sera detected 32 kDa as the major immunoreactive protein in all pathogenic serogroups. This protein reacted against specific LipL32 antisera indicating that this protein was LipL32. INTERPRETATION & CONCLUSION: The circulating serogroups of Leptospira have common nature of expression of proteins during human infection. Among several immunoreactive proteins, three (67, 45 and 32 kDa) were recognized as major antigens by both rabbit hyperimmune sera and patients sera while the 32 kDa protein was recognized as the major immunoreactive protein by homologous and heterologous patient sera. These conserved immunoreactive proteins could be utilized in developing indigenous diagnostic tests for leptospirosis.

Leptospiral proteins expressed during acute & convalescent phases of human leptospirosis.

BACKGROUND & OBJECTIVES: The available serological techniques for the diagnosis of leptospirosis have less sensitivity during the early stage of the disease. Understanding of leptospiral proteins expressed during acute and convalescent phases of leptospirosis, would be help the develop of new serodiagnostic strategies. Therefore, the present study was carried out to identify (i) an antigen that is conserved among the various pathogenic leptospira; (ii) best protein antigen to which immune response can be identified in the acute phase; and (iii) best protein antigen which is present in convalescent sera which can be used for seroepidemiological studies. METHODS: Quantitative immunoblot analysis was performed using acute and convalescent phase human sera along with sera from normal healthy individuals and from patients with typhoid, malaria and hepatitis as the controls. All the samples were analyzed for the leptospiral protein recognition by using IgM and IgG immunoblots. Leptospiral cell fractionation was performed using triton X-114 and lysozyme and further the conservation of leptospiral proteins was also performed. RESULTS: In confirmed cases of leptospirosis, the IgG recognition in acute phase sera was 30.2, 39.5, 27.9, 55.8 and 27.9 per cent for the leptospiral proteins p32, p41/42, p58, p62 and p82 respectively. The IgG has considerably increased to 65.1, 55.8, 46.5, 67.4 and 48.8 per cent against the same proteins during convalescent phase. The IgM recognition was 32.6 , 32.6, 30.2 and 37.2 per cent for acute phase sera and 32.6, 37.2, 44.2 and 41.9 per cent for convalescent phase sera for the leptospiral proteins p14, p25, p32 and p41/42, respectively. Leptospiral proteins like p62 and p82 were recognized among all the control groups with 3.3-15.3 per cent for IgG recognition. INTERPRETATION & CONCLUSION: Leptospiral protein p32 was found to be highly sensitive and specific and could be useful for the development of newer techniques for diagnosis and seroepidemiological studies. Combination of p32 and p41/42 for IgG and p14, p25, p32, p41/42 for IgM would increase the sensitivity of these techniques further.

Molecular tools in leptospirosis diagnosis and characterization of isolates.

The incidence of leptospirosis in human beings has been increasing in recent years. Early diagnosis and treatment can prevent complications and reduce mortality. The conventional laboratory methods for diagnosis rely on the demonstration of leptospires in clinical specimens, recovering the organisms in culture or the demonstration of antibodies to leptospires. Demonstration techniques have low sensitivity and specificity. Leptospires grow slowly and the positivity rate in culture is very low. Although microscopic agglutination test has been the cornerstone of serological diagnosis, the procedure is complex. New tests, like ELISA, dipstick test, lateral flow, etc, are relatively simple and rapid, but sensitivity is low during the early stages of the disease. The cross agglutination absorption test (CAAT) and typing with monoclonal antibodies (MCA) are the techniques used for serological characterization. These techniques are complicated and might not help in the case of certain serogroups. An alternate method for early diagnosis and characterization focuses on DNA-based techniques. Polymerase chain reaction (PCR), in situ hybridization etc are some of the methods used for early diagnosis, whereas restriction endonuclease analysis (REA), random amplified polymorphic DNA (RAPD) fingerprinting, arbitrarily primed PCR (AP-PCR), pulsed field gel electrophoresis (PFGE), ribotyping and DNA sequencing are useful for characterization. PCR is the most popular and quickest method for diagnosis. It can detect even if only a small number of organisms are present in a clinical sample. Fingerprinting tools such as RAPD, REA, RFLP, PFGE etc translate the complex genetic code into easily recognizable patterns, which facilitates characterization of the isolates up to sub-serovar level.

Leptospirosis disease burden estimation and surveillance networking in India.

Although leptospirosis is known to have occurred in India since the early years of the 20th century, no accurate data on disease burden exist. During the past two decades, leptospirosis cases have been reported with increasing frequency from different parts of the country. Several large outbreaks have occurred. In the year 2000, the Indian Council of Medical Research set up a Task Force on Leptospirosis. The Task Force conducted a multicentric study on disease burden due to leptospirosis. As part of the study, 3,682 patients with acute febrile illness, from 13 different centers in India, were investigated for the presence of current leptospiral infection using the Lepto-dipstick test. Of these patients, 469 (12.7%) were found to have leptospiral infection. The positivity rate ranged from 3.27% in the central zone to 28.16% in the southern zone. Fever, body aches and chills were the common symptoms observed. Urinary abnormalities, such as oliguria, yellow discoloration of urine and hematuria were found in 20%-40% of patients. Distribution of serogroups was studied based on microscopic agglutination test (MAT) titers. The southern zone had all the eleven serogroups in the panel, the eastern zone had nine, the northern zone eight, and the central and western zones had five circulating serogroups each. Among various risk factors studied, rat infestation of houses had the strongest association with leptospiral infection. Many other factors related to the environment, personal and occupational habits, etc, also had significant associations. The study had a few drawbacks. The Task Force has decided to continue the study with modified protocols to generate more accurate and detailed information about disease burden.