METHODS: A total of 69 ticks were collected from 27 domestic fowl (Gallus gallus domesticus), 2 jungle fowl (Gallus gallus) and 3 Siamese firebacks (Lophura diardi) at 10 locations (provinces) in Thailand. Ticks were identified and PCR was used to amplify Coxiella bacteria 16S rRNA, groEL and rpoB genes from the extracted tick DNA. MEGA6 was used to construct phylogenetic trees via a Maximum Likelihood method.
RESULTS: The phylogenetic analysis based on the 16S rRNA gene showed that the Coxiella sequences detected in this study grouped in the same clade with Coxiella sequences from the same tick genus (or species) reported previously. In contrast, rpoB gene of the Coxiella bacteria detected in this study did not cluster together with the same tick genus reported previously. Instead, they clustered by geographical distribution (Thai cluster and Malaysian cluster). In addition, phylogenetic analysis of the groEL gene (the chaperonin family) showed that all Coxiella bacteria found in this study were grouped in the same clade (three sister groups).
CONCLUSIONS: To our knowledge, we found for the first time rpoB genes of Coxiella-like bacteria in Haemaphysalis wellingtoni ticks forming two distinct clades by phylogenetic analysis. This may be indicative of a horizontal gene transfer event.
METHODS: We did an environmentally stratified, population-based, cross-sectional survey across households in the Kudat, Kota Marudu, Pitas, and Ranau districts in northern Sabah, Malaysia, encompassing a range of ecologies. Using blood samples, the transmission intensity of P knowlesi and other malaria species was measured by specific antibody prevalence and infection detected using molecular methods. Proportions and configurations of land types were extracted from maps derived from satellite images; a data-mining approach was used to select variables. A Bayesian hierarchical model for P knowlesi seropositivity was developed, incorporating questionnaire data about individual and household-level risk factors with selected landscape factors.
FINDINGS: Between Sept 17, 2015, and Dec 12, 2015, 10 100 individuals with a median age of 25 years (range 3 months to 105 years) were sampled from 2849 households in 180 villages. 5·1% (95% CI 4·8-5·4) were seropositive for P knowlesi, and marked historical decreases were observed in the transmission of Plasmodium falciparum and Plasmodium vivax. Nine Plasmodium spp infections were detected. Age, male sex, contact with macaques, forest use, and raised house construction were positively associated with P knowlesi exposure, whereas residing at higher geographical elevations and use of insecticide were protective. Agricultural and forest variables, such as proportions and fragmentation of land cover types, predicted exposure at different spatial scales from households.
INTERPRETATION: Although few infections were detected, P knowlesi exposure was observed in all demographic groups and was associated with occupational factors. Results suggest that agricultural expansion and forest fragmentation affect P knowlesi exposure, supporting linkages between land use change and P knowlesi transmission.
FUNDING: UK Medical Research Council, Natural Environment Research Council, Economic and Social Research Council, and Biotechnology and Biosciences Research Council.
RESULTS: Anti-ICAM-1 and CD36 monoclonal antibodies were able to inhibit and reverse P. falciparum binding of lab and recently adapted patient isolates in vitro. However, reversal of binding was incomplete and varied in its efficiency between parasite isolates.
CONCLUSIONS: The results show that, as a proof of concept, disturbing existing ligand-receptor interactions is possible and could have potential therapeutic value for severe malaria. The variation seen in the degree of reversing existing binding with different parasite isolates and the incomplete nature of reversal, despite the use of high affinity inhibitors, suggest that anti-adhesion approaches as adjunct therapies for severe malaria may not be effective, and the focus may need to be on inhibitory approaches such as vaccines.
METHODS: A total of 359 pregnant women living in the rural communities of Taiz governorate were enrolled in this study by house-to-house visits. Data were collected using a pre-designed questionnaire, and blood samples were collected and tested for the detection of anti- T. gondii IgM and IgG antibodies by enzyme-linked immunosorbent assay.
RESULTS: The prevalence of T. gondii infection among pregnant women in this study was 46.2% (166/359). Bivariate analysis identified the age of ≥ 30 years (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.09-2.65, P = 0.019) and unimproved water sources (OR = 2.2; 95% CI = 1.10-4.55, P = 0.023) as factors associated with T. gondii infection among pregnant women. The multivariable analysis, however, identified unimproved water sources as an independent risk factor (adjusted OR = 2.4; 95% CI = 1.16-5.0, P = 0.018) associated with T. gondii infection among pregnant women.
CONCLUSIONS: Pregnant women in the rural communities of Taiz, Yemen are at high risk of contracting T. gondii infection. Unimproved water sources (wells, water streams and water tanks) are significantly associated with T. gondii infection and should be considered in prevention and control strategies, especially among pregnant women.