Perceived needs of disease vector control programs: A review and synthesis of (sub)national assessments from South Asia and the Middle East.

Systems for disease vector control should be effective, efficient, and flexible to be able to tackle contemporary challenges and threats in the control and elimination of vector-borne diseases. As a priority activity towards the strengthening of vector control systems, it has been advocated that countries conduct a vector-control needs assessment. A review was carried out of the perceived needs for disease vector control programs among eleven countries and subnational states in South Asia and the Middle East. In each country or state, independent teams conducted vector control needs assessment with engagement of stakeholders. Important weaknesses were described for malaria, dengue and leishmaniases regarding vector surveillance, insecticide susceptibility testing, monitoring and evaluation of operations, entomological capacity and laboratory infrastructure. In addition, community mobilization and intersectoral collaboration showed important gaps. Countries and states expressed concern about insecticide resistance that could reduce the continued effectiveness of interventions, which demands improved monitoring. Moreover, attainment of disease elimination necessitates enhanced vector surveillance. Vector control needs assessment provided a useful planning tool for systematic strengthening of vector control systems. A limitation in conducting the vector control needs assessment was that it is time- and resource-intensive. To increase the feasibility and utility of national assessments, an abridged version of the guidance should focus on operationally relevant topics of the assessment. Similar reviews are needed in other regions with different contextual conditions.

The burden of dengue and force of infection among children in Kerala, India; seroprevalence estimates from Government of Kerala-WHO Dengue study.

Background: Dengue shows high geographic heterogeneity within and across endemic countries. In the context of increasing burden and predicted outbreaks due to climate change, understanding the heterogeneity will enable us to develop region specific targeted interventions, including vaccination. World Health Organisation (WHO) suggests standard methodologies to study the burden and heterogeneity at national and subnational levels. Regional studies with robust and standard methodology to capture heterogeneity are scarce. We estimated the seroprevalence of dengue in children aged 9-12 years and the force of infection in Kerala, India, from where Zika cases also have been reported recently. Methods: We conducted a school-based cross-sectional survey in 38 clusters; selected by stratified random sampling, representing rural, urban, high burden and low-burden administrative units. Validation of Indirect IgG ELISA was done by Plaque Reduction Neutralization Test (PRNT90) using the local isolates of all four serotypes. Force of infection (FOI) was estimated using the WHO-FOI calculator. We conducted a follow-up survey among a subsample of seronegative children, to estimate the rate of sero-conversion. Results: Among 5236 children tested, 1521 were positive for anti-dengue IgG antibody. The overall seroprevalence in the state was 29% (95% CI 24.1-33.9). The validity corrected seroprevalence was 30.9% in the overall sample, 46.9% in Thiruvananthapuram, 26.9% in Kozhikkode and 24.9% in Kollam. Age-specific seroprevalence increased with age; 25.7% at 9 years, 29.5% at 10 years, 30.9% at 11 years and 33.9% at 12 years. Seroprevalence varied widely across clusters (16.1%-71.4%). The estimated force of infection was 3.3/100 person-years and the seroconversion rate was 4.8/100 person-years. 90% of children who tested positive were not aware of dengue infection. All the four serotypes were identified in PRNT and 40% of positive samples had antibodies against multiple serotypes. Interpretation: The study validates the WHO methodology for dengue serosurveys and confirms its feasibility in a community setting. The overall seroprevalence in the 9-12 year age group is low to moderate in Kerala; there are regional variations; high burden and low burden clusters co-exist in the same districts. The actual burden of dengue exceeds the reported numbers. Heterogeneity in prevalence, the high proportion of inapparent dengue and the hyperendemic situation suggest the need for region-specific and targeted interventions, including vaccination. Funding: World Health Organization.

Therapeutic efficacy of artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in four malaria endemic states of India.

BACKGROUND: Malaria is a major public health problem in India and accounts for about 88% of malaria burden in South-East Asia. India alone accounted for 2% of total malaria cases globally. Anti-malarial drug resistance is one of the major problems for malaria control and elimination programme. Artemether-lumefantrine (AL) is the first-line treatment of uncomplicated Plasmodium falciparum in north eastern states of India since 2013 after confirming the resistance against sulfadoxine-pyrimethamine. In the present study, therapeutic efficacy of artemether-lumefantrine and k13 polymorphism was assessed in uncomplicated P. falciparum malaria. METHODS: This study was conducted at four community health centres located in Koraput district of Odisha, Bastar district of Chhattisgarh, Balaghat district of Madhya Pradesh and Gondia district of Maharashtra state. Patients with uncomplicated P. falciparum malaria were administered with fixed dose combination (6 doses) of artemether-lumefantrine for 3 days and clinical and parasitological response was recorded up to 28 days as per World Health Organization protocol. Nucleotide sequencing of msp1 and msp2 gene was performed to differentiate between recrudescence and reinfection. Amplification and sequencing of k13 propeller gene region covering codon 450-680 was also carried out to identify the polymorphism. RESULTS: A total 376 malaria patients who fulfilled the enrolment criteria as well as consented for the study were enrolled. Total 356 patients were followed up successfully up to 28 days. Overall, the adequate clinical and parasitological response was 98.9% and 99.4% with and without PCR correction respectively. No case of early treatment failure was observed. However, four cases (1.1%) of late parasitological failure were found from the Bastar district of Chhattisgarh. Genotyping of msp1 and msp2 confirmed 2 cases each of recrudescence and reinfection, respectively. Mutation analysis of k13 propeller gene showed one non-synonymous mutation Q613H in one isolate from Bastar. CONCLUSIONS: The study results showed that artemether-lumefantrine is highly effective in the treatment of uncomplicated P. falciparum malaria among all age groups. No functional mutation in k13 was found in the study area. The data from this study will be helpful in implementation of artemether-lumefantrine in case of treatment failure by artesunate plus sulfadoxine-pyrimethamine.

Molecular epidemiology and evolutionary analysis of dengue virus type 2, circulating in Delhi, India.

Dengue virus type 2 (DENV-2) has been associated with severe dengue outbreaks in many countries including India. Its predominance was recorded nearly after a decade in the capital city, Delhi in 2013. The present study characterizes DENV-2 circulated during 2013-2014. Analysis based on envelope (E) gene showed the presence of two clades (I and II) of DENV-2, within the Cosmopolitan genotype. Analysis of time of most recent common ancestor revealed the existence of clade I for more than a decade (95 % HPD 13-16 years) however, clade II showed comparatively recent emergence (95 % HPD 5-13 years). Presence of different clades is of high significance as this may result in increased virus transmission and major outbreaks. Further, the presence of a unique amino acid substitution, Q325H was also observed in an isolate; 14/D2/Del/2013 (KT717981). This substitution falls in immune epitope (epitope id: 150268) and may have important role in host immune response.

First indigenous transmission of Japanese Encephalitis in urban areas of National Capital Territory of Delhi, India.

OBJECTIVE: Until 2010, no Japanese encephalitis (JE) had been reported from Delhi. Upon report of four confirmed cases of JE in September 2011, detailed investigations were carried out to determine whether the cases were imported or indigenous. METHODS: Entomological surveys were carried out and all mosquito pools were tested for the detection of JE virus by ELISA method using specific monoclonal antibody. Human blood samples from contacts of the patients were tested by IgM-captured ELISA method. Pig's blood samples were also tested for the detection of JE virus. RESULTS: Culex tritaeniorhynchus, Culex vishnui and Culex pseudovishnui mosquitoes were found. In contrast to rural areas, their breeding habitats were different in the city. 19 pools were tested. JE virus was detected in two pools of Cx. tritaeniorhynchus females reared from field-collected larvae, indicating vertical transmission. One pool of Cx. vishnui was also positive. This is the first report for the detection of JE virus in mosquitoes from Delhi. JE IgM antibodies in five contacts/residents indicate recent infection. JE virus was also detected in pigs. CONCLUSION: Present analysis shows that of four reported JE cases, three were confirmed indigenous, indicating that the virus is multiplying in the city. Mapping of infected JE vector mosquitoes in the cities is required for preventive measures to contain further spread of the disease.

A review of Japanese encephalitis in Uttar Pradesh, India.

BACKGROUND: Japanese encephalitis (JE) is a major public health problem in India. When the first case was reported in 1955, the disease was restricted to south India. The disease spread to north India in 1978 from where extensive and recurrent outbreaks of JE have been reported ever since. An attempt has been made to review the epidemiology of JE over the past 30 years and suggestions made for its prevention and control. METHODS: An epidemiological profile of JE (1978-2009) has been compiled and analysed to understand the trend and status of the disease. RESULTS: In India, while 24 states are endemic for JE, Uttar Pradesh contributed more than 75% of cases during the recent past. Over the years, the seasonal trend has changed and the epidemic peak of the disease has advanced by one month. CONCLUSION: JE is closely associated with the pattern of precipitation, flooding and rice production systems. Analysis of trends and influencing factors will help in designing suitable strategies for the prevention and control of JE in the country. Continuous monitoring of vector populations and JE virus infection rates in vector mosquitoes will help in predicting an outbreak and in taking effective intervention measures.

First dengue virus detection in Aedes albopictus from Delhi, India: its breeding ecology and role in dengue transmission.

OBJECTIVE: To report dengue virus and its disease transmission in Aedes albopictus in the National Capital Territory of Delhi, India. METHODS: Monthly Aedes surveys were carried out in 126 urban localities of Delhi in 2008 and 2009. Pools of all three species of Aedes mosquitoes were tested for Dengue virus (DENV) using an antigen-capture enzyme-linked immunosorbent assay. RESULTS: Aedes aegypti was the most prevalent species, breeding throughout the year. Aedes albopictus was found in 9.52% of surveyed localities including the central urban part of Delhi, in March and from August to October. Aedes albopictus and Aedes vittatus are adapting to breed in manmade containers in the urban areas of Delhi in addition to their natural habitats of bamboo bushes and rock pits. Of the 229 pools of Ae. aegypti and 34 pools of Ae. albopictus tested, 10.5% and 11.76% were positive for dengue virus, respectively. No dengue virus infection was recorded in Ae. vittatus. CONCLUSION: This is the first report of dengue virus in Ae. albopictus from north India. Because DENV was detected in Ae. albopictus, which adapted to manmade containers, both its spread and transmission dynamics should be checked.

Management of malaria threat following tsunami in Andaman & Nicobar Islands, India and impact of altered environment created by tsunami on malaria situation of the islands.

Andaman & Nicobar Islands (Indian Territory) are situated in the Bay of Bengal and endemic for malaria with perennial transmission. Anopheles sundaicus which prefers to breed in brackish water, is known as the main vector for malaria and maintains high endemicity of malaria. Tsunami waves entered the inhabited coastal areas, caused heavy devastation and left large areas inundated causing exceptionally high breeding sources for vector mosquitoes of malaria. The disaster created a new habitat suitable for the proliferation of malaria and other disease-carrying mosquitoes besides making thousands of people homeless. They were living in temporary open shelters, getting more exposed to mosquito bites. The population already had existing high parasite load. Hence, there was a real threat of malaria outbreak in the area. However, malaria was effectively controlled due to strategic planning and timely remedial measures. Malaria situation was monitored closely and epidemiological data of three subsequent years from 2005 to 2007 after tsunami were analysed and compared with pre-tsunami malaria data from 1986 to 2004. In this paper, effect of tsunami on malaria profile in these islands has been discussed along with action taken for its control.