Triatoma dimidiata Infestation in Chagas Disease Endemic Regions of Guatemala: Comparison of Random and Targeted Cross-Sectional Surveys

Chagas disease is a vector-borne parasitic zoonosis endemic throughout South and Central America and Mexico. Guatemala is engaged in the Central America Initiative to interrupt Chagas disease transmission. A major strategy is the reduction of Triatoma dimidiata domiciliary infestations through indoor application of residual insecticides. Successful control of T. dimidiata will depend on accurate identification of areas at greatest risk for infestation. Initial efforts focused primarily on targeted surveys of presumed risk factors and suspected infestation to define intervention areas. This policy has not been evaluated and might not maximize the effectiveness of limited resources if high prevalence villages are missed or low prevalence villages are visited unnecessarily. We compare findings from the targeted surveys to concurrent random surveys in two primary foci of Chagas disease transmission in Guatemala to evaluate the performance of the targeted surveys. Our results indicate that random surveys performed better than targeted surveys and should be considered over targeted surveys when reliability of risk factors has not been evaluated, identify useful environmental factors to predict infestation, and indicate that infestation risk varies locally. These findings are useful for decision-makers at national Chagas Disease control programs in Central America, institutions supporting development efforts, and funding agencies

Climate change and One Health

The journal The Lancet recently published a countdown on health and climate change. Attention was focused solely on humans. However, animals, including wildlife, livestock and pets, may also be impacted by climate change. Complementary to the high relevance of awareness rising for protecting humans against climate change, here we present a One Health approach, which aims at the simultaneous protection of humans, animals and the environment from climate change impacts (climate change adaptation). We postulate that integrated approaches save human and animal lives and reduce costs when compared to public and animal health sectors working separately. A One Health approach to climate change adaptation may significantly contribute to food security with emphasis on animal source foods, extensive livestock systems, particularly ruminant livestock, environmental sanitation, and steps towards regional and global integrated syndromic surveillance and response systems. The cost of outbreaks of emerging vector-borne zoonotic pathogens may be much lower if they are detected early in the vector or in livestock rather than later in humans. Therefore, integrated community-based surveillance of zoonoses is a promising avenue to reduce health effects of climate change

Phylogeographic pattern and extensive mitochondrial DNA divergence disclose a species complex within the Chagas disease vector Triatoma dimidiata.

ABSTARCT: Previous studies have shown that "bioequivalent" generic products of vancomycin are less effective in vivo against Staphylococcus aureus than the innovator compound. Considering that suboptimal bactericidal effect has been associated with emergence of resistance, we aimed to assess in vivo the impact of exposure to innovator and generic products of vancomycin on S. aureus susceptibility. A clinical methicillin-resistant S. aureus (MRSA) strain from a liver transplant patient with persistent bacteremia was used for which MIC, minimum bactericidal concentration (MBC), and autolytic properties were determined. Susceptibility was also assessed by determining a population analysis profile (PAP) with vancomycin concentrations from 0 to 5 mg/liter. ICR neutropenic mice were inoculated in each thigh with ∼7.0 log(10) CFU. Treatment with the different vancomycin products (innovator and three generics; 1,200 mg/kg of body weight/day every 3 h) started 2 h later while the control group received sterile saline. After 24 h, mice were euthanized, and the thigh homogenates were plated. Recovered colonies were reinoculated to new groups of animals, and the exposure-recovery process was repeated until 12 cycles were completed. The evolution of resistance was assessed by PAP after cycles 5, 10, 11, and 12. The initial isolate displayed reduced autolysis and higher resistance frequencies than S. aureus ATCC 29213 but without vancomycin-intermediate S. aureus (VISA) subpopulations. After 12 cycles, innovator vancomycin had significantly reduced resistant subpopulations at 1, 2, and 3 mg/liter, while the generic products had enriched them progressively by orders of magnitude. The great capacity of generic vancomycin to select for less susceptible organisms raises concerns about the role of therapeutic inequivalence of any antimicrobial on the epidemiology of resistance worldwide

Estimates of effect of significant environmental risk factors on <i>Triatoma dimidiata</i> intradomiciliary prevalence >5%.

<p>Key to risk factor abbreviations: LST, land surface temperature; MIR, middle infrared; NDVI, normalized difference vegetation index; RH, relative humidity.</p><p>Univariate logistic regression models were developed to investigate the effect of each environmental covariate on <i>Triatoma dimidiata</i> intradomiciliary village prevalence >5% by survey and department. Odds ratios (OR) and 95% confidence intervals for significant risk factors are reported. Land cover classes represent the proportion of each land cover type within a 2 km buffer of analyzed villages.</p

Effects of Permethrin-impregnated Bed Nets on Malaria Vectors of Northern Guatemala&apos;

The authors evaluated the effects on malaria vectors of bed nets impregnated with permethrin over the course of a 16month controlled study in four communities of Northern Guatemala. Anopheles albimanus and An. vestitipennis were the known malaria vectors in the area. Households were allocated to one of three experimental groups: those receiving bed nets impregnated with 500 mglm2 of permethrin, those receiving untreated bed nets, and those where no intervention measures were taken. The impact of the treated and untreated bed nets on mosquito abundance, behavior, and mortality was determined by indoorloufdoor night-bite mosquito collections, morning pyrethrum spray collections, inspection of bed net surfaces for dead mosquitoes, and capture-release-recapture studies. The duration of the treated nets&apos; residual insecticide effect was assessed by modified WHO cone field bioassays, and their pyrethrin content was estimated by gas-liquid chromatography analysis. The most important observation was that fewer mosquitoes were found to be resting in the households with treated bed nets. The treated nets probably functioned by both repelling and killing vector mosquitoes. Capture-release-recapture studies showed exit rafes from houses wifh treated nets were higher (94%) than thosefrom control houses (72%), a finding that suggests repellency. However, no significant differences were noted between the indoor night-bite mosquito collections at houses with and without treated nets. The horizontal surfaces of treated bed nets were nearly 20 times more likely to contain dead anopheline mosquitoes than were the comparable surfaces of untreated nets. The bioassays indicated that unwashed permethrin-impregnated bed nets retained their insecticidal activity for 6 months after treatment

Toward Chagas disease elimination: Neonatal screening for congenital transmission in rural communities

Chagas disease is a neglected tropical disease that continues to affect populations living in extreme poverty in Latin America. After successful vector control programs, congenital transmission remains as a challenge to disease elimination. We used the PRECEDE-PROCEED planning model to develop strategies for neonatal screening of congenital Chagas disease in rural communities of Guatemala. These communities have persistent high triatomine infestations and low access to healthcare. We used mixed methods with multiple stakeholders to identify and address maternal-infant health behaviors through semi-structured interviews, participatory group meetings, archival reviews and a cross-sectional survey in high risk communities. From December 2015 to April 2016, we jointly developed a strategy to illustratively advertise newborn screening at the Health Center. The strategy included socioculturally appropriate promotional and educational material, in collaboration with midwives, nurses and nongovernmental organizations. By March 2016, eight of 228 (3.9%) pregnant women had been diagnosed with T. cruzi at the Health Center. Up to this date, no neonatal screening had been performed. By August 2016, seven of eight newborns born to Chagas seropositive women had been parasitologically screened at the Health Center, according to international standards. Thus, we implemented a successful community-based neonatal screening strategy to promote congenital Chagas disease healthcare in a rural setting. The success of the health promotion strategies developed will depend on local access to maternal-infant services, integration with detection of other congenital diseases and reliance on community participation in problem and solution definition

Phylogenetic analysis of viruses sequenced by swab-NGS and VI-NGS

Phylogenetic analysis of influenza A viruses from blue winged teal samples