Introduction Selection of the artificial membrane feeding technique and blood meal source has been recognized as key considerations in mass rearing of vectors. Methodology Artificial membrane feeding techniques, namely, glass plate, metal plate, and Hemotek membrane feeding method, and three blood sources (human, cattle, and chicken) were evaluated based on feeding rates, fecundity, and hatching rates of Aedes aegypti. Significance in the variations among blood feeding was investigated by one-way ANOVA, cluster analysis of variance (ANOSIM), and principal coordinates (PCO) analysis. Results Feeding rates of Ae. aegypti significantly differed among the membrane feeding techniques as suggested by one-way ANOVA (p < 0.05). The metal plate method was identified as the most efficient and cost-effective feeding technique. Blood feeding rate of Ae. aegypti was higher with human blood followed by cattle and chicken blood, respectively. However, no significant difference was observed from the mosquitoes fed with cattle and human blood, in terms of fecundity, oviposition rate, and fertility as suggested by one-way ANOVA (p > 0.05). Conclusions Metal plate method could be recommended as the most effective membrane feeding technique for mass rearing of Ae. aegypti, due to its high feeding rate and cost effectiveness. Cattle blood could be recommended for mass rearing Ae. aegypti.

BackgroundLarval indices such as Premise Index (PI), Breteau Index (BI) and Container Index (CI) are widely used to interpret the density of dengue vectors in surveillance programmes. These indices may be useful for forecasting disease outbreaks in an area. However, use of the values of these indices as alarm signals is rarely considered in control programmes. Therefore, the current study aims to propose threshold values for vector indices based on an empirical modeling approach for the Kandy District of Sri Lanka.MethodsMonthly vector indices, viz PI, BI and CI, for Aedes aegypti and Aedes albopictus, of four selected dengue high risk Medical Officer of Health (MOH) areas in the Kandy District from January 2010 to August 2017, were used in the study. Gumbel frequency analysis was used to calculate the exceedance probability of quantitative values for each individual larval index within the relevant MOH area, individually and to set up the threshold values for the entomological management of dengue vectors.ResultsAmong the study MOH areas, Akurana indicated a relatively high density of both Ae. aegypti and Ae. albopictus, while Gangawata Korale MOH area had the lowest. Based on Ae. aegypti, threshold values were defined for Kandy as low risk (BIagp > 1.77), risk (BIagp > 3.23), moderate risk (BIagp > 4.47) and high risk (BIagp > 6.23). In addition, PI > 6.75 was defined as low risk, while PI > 9.43 and PI>12.82 were defined as moderate and high risk, respectively as an average.ConclusionsThreshold values recommended for Ae. aegypti (primary vector for dengue) along with cut-off values for PI (for Ae. aegypti and Ae. albopictus), could be suggested as indicators for decision making in vector control efforts. This may also facilitate the rational use of financial allocations, technical and human resources for vector control approaches in Sri Lanka in a fruitful manner.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-2961-y) contains supplementary material, which is available to authorized users.

BackgroundComprehensive understanding of risk factors related to socio-economic and demographic status and knowledge, attitudes and practices (KAP) of local communities play a key role in the design and implementation of community-based vector management programmes, along with the identification of gaps in existing control activities.MethodsA total of 10 Medical Officers of Health (MOH) areas recording high dengue incidence over the last five years were selected from Colombo (n = 5) and Kandy (n = 5) Districts, Sri Lanka. From each MOH area, 200 houses reporting past dengue incidence were selected randomly as test group (n = 1000 for each district) based on the dengue case records available at relevant MOH offices. Information on socio-economic and demographic status and knowledge, attitudes and practices were gathered using an interviewer administered questionnaire. The control group contained 200 households from each MOH area that had not reported any dengue case and the same questionnaire was used for the assessment (n = 1000 for each district). Statistical comparisons between the test and control groups were carried out using the Chi-square test of independence, cluster analysis, analysis of similarities (ANOSIM) and multi-dimensional scaling (MDS) analysis.ResultsSignificant differences among the test and control groups in terms of basic demographic and socio-economic factors, living standards, knowledge, attitude and practices, were recognized (P < 0.05 at 95% level of confidence). The test group indicated similar risk factors, while the control group also shared more or less similar characteristics as depicted by the findings of cluster analysis and ANOSIM. Findings of the present study highlight the importance of further improvement in community education, motivation and communication gaps, proper coordination and integration of control programmes with relevant entities. Key infrastructural risk factors such as urbanization and waste collection, should be further improved, while vector controlling entities should focus more on the actual conditions represented by the public on knowledge, attitudes and personal protective practices.ConclusionsThe design of flexible and community friendly intervention programmes to ensure the efficacy and sustainability of controlling dengue vectors through community based integrated vector management strategies, is recommended.

Gastrointestinal (GI) parasitic infection is a serious issue in cattle management. The effects of GI parasites may vary with age, sex of cattle, nutritional condition, and severity of infection. Prevalence of GI parasites among cattle population in Gampaha District has not been studied and there is no published study available. A total of 45 farms rearing cattle were selected randomly in three areas, namely, Kelaniya, Ganemulla, and Welisara, under three Veterinary Surgeon Divisions (VSD) in Gampaha District (Mahara, Gampaha, and Welisara). Freshly voided cattle fecal samples were collected randomly from the selected farms during March 2017–December 2017. Out of 163 cattle and buffaloes examined, 13.39% (n=22) were positive for eggs of one or more species of GI parasites. The prevalence of parasitic infection was higher in buffaloes (31.25%, 5/16) as compared to that of cows (11.56%, 21/147), but the difference was not significant (P >0.05). Hookworms (Bunostomum spp.), whipworms (Trichuris spp.), digenetic trematodes (Paramphistomum spp.), cestodes (Moniezia spp.), and oocysts of protozoans (coccidians) were found during the study. The nontreated animals indicated the highest percentage of parasitic infections accounting for 46.67% (n= 14), followed by partially treated individuals (15.15%, n= 5). GI parasite prevalence in males was higher when compared to that of females, but the difference was nonsignificant (P >0.05). General Linear Modelling (GLM) revealed that the effect of treatment status was significantly associated with the prevalence of GI parasites. The calves and yearlings had the highest rate of GI parasitic infections. The highest infection rate was observed at Kelaniya, followed by Welisara. Future investigations are necessary to evaluate the economic impact of GI parasites in the study areas.

BackgroundSocio-economic, demographic factors and Knowledge Attitude Practices (KAPs) have been recognized as critical factors that influence the incidence and transmission of dengue epidemics. However, studies that characterize above features of a risk free or low risk population are rare. Therefore, the present study was conducted to characterize the household related, demographic, socio-economic factors and KAPs status of five selected dengue free communities.MethodAn analytical cross-sectional survey was conducted on selected demographic, socio-economic, household related and KAPs in five selected dengue free communities living in dengue risk areas within Kandy District, Central Province, Sri Lanka. Household heads of 1000 randomly selected houses were interviewed in this study. Chi-square test for independence, cluster analysis and Principal Coordinates (PCO) analysis were used for data analysis.ResultsKnowledge and awareness regarding dengue, (prevention of the vector breeding, bites of mosquitoes, disease symptoms and waste management) and attitudes of the community (towards home gardening, composting, waste management and maintenance of a clean and dengue free environment) are associated with the dengue free status of the study populations.ConclusionsThe vector controlling authorities should focus on socio-economic, demographic and KAPs in stimulating the community to cooperate in the integrated vector management strategies to improve vector control and reduce transmission of dengue within Kandy District.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-2995-y) contains supplementary material, which is available to authorized users.

BackgroundAnopheles culicifacies, the major vector of malaria in Sri Lanka, is known to breed in clean and clear water. The main objective of the study was to detect the breeding habitat diversity of An. culicifacies.MethodsPotential larval habitats for Anopheles mosquitoes were surveyed on a monthly basis for 17 months (January 2011–June 2012) in four different selected sampling sites (Murthankulam, Kommnaimottai, Paranamadawachchiya and Kokmotawewa) in Trincomalee District of Sri Lanka.ResultsA total of 2,996 larval specimens representing 13 Anopheles species were reported from 16 different breeding habitats. According to density criterion, An. culicifacies, Anopheles subpictus, Anopheles barbirostris, Anopheles peditaeniatus and Anopheles nigerrimus were dominant. Anopheles nigerrimus, An. subpictus and An. peditaeniatus were observed as constant in relation to their distribution. The most productive breeding site for An. culicifacies was drains filled with waste water in remote areas; the second highest productivity was found in built wells.ConclusionsThese results indicate that An. culicifacies has adapted to breed in a wide range of water bodies including waste water collections although they were earlier considered to breed only in clean and clear water.

BackgroundStudies of host preference patterns in blood-feeding anopheline mosquitoes are crucial to incriminating malaria vectors. However, little information is available on host preferences of Anopheles mosquitoes in Sri Lanka.MethodsAdult Anopheles mosquitoes were collected from five selected sentinel sites in Trincomalee District during June–September 2011. Each blood-fed mosquito was processed on filter papers. DNA was extracted using the dried blood meal protocol of the QIAmp DNA mini kit. A multiplexed, real-time PCR assay targeting eight animals was developed for two panels to identify the host meal of Anopheles. Human blood index (HBI), forage ratio (FR) and host feeding index (HFI) were calculated.ResultsA total of 280 field-caught, freshly engorged female mosquitoes belonging to 12 anopheline species were analysed. The overall HBI and HFI in the present study were low indicating that humans were not the preferred host for the tested anopheline species. Nevertheless, a small proportion engorged Anopheles aconitus, Anopheles culicifacies, Anopheles barbirostris, Anopheles annularis, Anopheles subpictus, Anopheles peditaeniatus, Anopheles pseudojamesi, and Anopheles barbumbrosus contained human blood.ConclusionThe presence of human blood in mosquito species indicates the possibility of them transmitting malaria. Further studies on vector competence are needed to determine the role of each of the above anopheline species as efficient vectors of malaria.

The present works reviewed the existing information on leishmaniasis in Sri Lanka and in other countries, focusing on challenges of controlling leishmaniasis in the country, in an outbreak. Evidence from recent studies suggests that there is a possibility of a leishmaniasis outbreak in Sri Lanka in the near future. Difficulty of early diagnosis due to lack of awareness and unavailability or inadequacy of sensitive tests are two of the main challenges for effective case management. Furthermore, the absence of a proper drug for treatment and lack of knowledge about vector biology, distribution, taxonomy and bionomics, and reservoir hosts make the problem serious. The evident potential for visceralization in the cutaneous variant of L. donovani in Sri Lanka may also complicate the issue. Lack of knowledge among local communities also reduces the effectiveness of vector and reservoir host control programs. Immediate actions need to be taken in order to increase scientific knowledge about the disease and a higher effectiveness of the patient management and control programs must be achieved through increased awareness about the disease among general public and active participation of local community in control activities.