Abstract. The geographic distribution of Plasmodium vivax circumsporozoite protein phenotypes from patient blood used to infect colonized Anopheles albimanus and An. pseudopunctipennis was investigated in southern Mexico. Parasite phenotype types were determined in blood samples by a polymerase chain reaction and oligoprobe hybridization or by immunofluorescent assay of sporozoites. The proportion of infected mosquitoes and the number of oocysts per mosquito confirmed previous in vitro observations indicating that An. albimanus is more susceptible to VK210 and that An. pseudopunctipennis is more susceptible to VK247. All patients living on the coast were infected with VK210 and most patients living above 170 meters above sea level had VK247. Both phenotypes infected patients from intermediate altitudes. These results concur with the distribution of the anophelines, indicating that An. albimanus is the main vector of the phenotype VK210, but that An. pseudopunctipennis transmits both phenotypes. These conditions have direct implications on parasite transmission rates and malaria epidemiology in Mexico.

Background Proximity to roadways increases the risk of asthma in developed countries; however, relatively little is known about this relationship in developing countries, where rapid and uncontrolled growth of cities has resulted in urban sprawl and heavy traffic volumes. Objective Determine the effect of distance from a heavily transited avenue on asthma symptoms and quantitative respiratory outcome measures in a peri-urban shanty town in Lima, Peru. Methods We enrolled 725 adolescents aged 13–15 years, administered a survey on asthma symptoms and measured spirometry, response to allergy skin testing and eNO. We calculated distances from the main avenue for all households and measured indoor PM in 100 households. We used multivariable regression to model the risk of asthma symptoms, risk of atopy, eNO and FEV1/FVC as a function of distance. Results Compared against 384 meters, the odds of current asthma symptoms in households living within 100 meters increased by a factor of 2 (p<0.05). The odds of atopy increased by a factor of 1.07 for every 100 meters difference in the distance from the avenue (p=0.03). We found an inverse relationship in pre-bronchodilator FEV1/FVC and distance to the avenue in females (p=0.01) but not in males. We did not find an association between eNO or household PM levels and distance. Conclusion Living in close proximity to a high traffic-density avenue in a peri-urban community in Peru was associated with a greater risk of asthma symptoms and atopy. Regulation of mobile source pollutants in peri-urban areas of developing countries may help reduce the burden of asthma symptoms and atopy.

The susceptibilities to coindigenous Plasmodium vivaxof colonized Anopheles albimanus and Anopheles pseudopunctipennis from southern Mexico were investigated by simultaneous feeding with infected blood obtained from patients. The genes encoding circumsporozoite protein variant types (VK210 and VK247) in blood samples were determined by PCR and oligonucleotide probe hybridization. A. albimanus was more susceptible to VK210, and A. pseudopunctipennis was more susceptible to VK247.

Landscape characteristics that may influence important components of the Anopheles albimanus Wiedemann life cycle, including potential breeding sites, suitable diurnal resting sites, and possible sources of blood meals, were analyzed at 14 villages in a malarious area of southern Mexico. An. albimanus adults were collected weekly in each village using UV-light traps between July 1991 and August 1992. Based on rainfall, the study was divided into 6 seasonal periods. Villages were considered to have high mosquito abundance when >5 mosquitoes per trap per night were collected during any 1 of the 6 seasonal periods. The extension and frequency of 11 land cover types surrounding villages were determined using aerial photographs and subsequently verified through field surveys. Elevation was the main landscape feature that separated villages with low and high mosquito abundance. All villages with high mosquito abundance were below 25 m. Transitional and mangrove land cover types were found only in the high mosquito abundance group. Flooded areas as potential breeding sites and potential adult resting sites in unmanaged pastures were significantly more frequent in areas surrounding villages with high mosquito abundance. No significant differences in density of cattle and horses were found among village groups. Overall, surrounding breeding sites located at low elevations in flooded unmanaged pastures seemed to be the most important determinants of An. albimanus adult abundance in the villages.

The susceptibility to two coindigenous Plasmodium vivax Grassi & Feletti phenotypes VK210 and VK247 of three colonized Anopheles albimanus Wiedemann strains (white-striped, green and brown) from southern Mexico was investigated. Mosquitoes of the three strains were simultaneously fed with P. vivax-infected patient blood and examined 1 wk later for the presence of oocysts. The circumsporozoite protein phenotype type (VK210 and VK247) was determined by immunoflorescence of salivary gland sporozoites using monoclonal antibodies. The proportions of specimens infected and the number of oocyst per mosquito indicated that all mosquito strains were more susceptible to the phenotype VK210 than to VK247, but the white-striped strain was more susceptible to both parasite phenotypes than the other two strains.

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The long non-coding RNA (lncRNA) Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) maintains the integrity of the intestinal epithelial barrier and regulates local inflammation. However, its influences on intestinal microbial communities and tissue susceptibility to cancer development remain unexplored. Here, we report that MALAT1 regulates host anti-microbial response gene expression and the composition of mucosal-associated microbial communities in a region-specific manner. In the APC mutant mouse model of intestine tumorigenesis, knocking out MALAT1 results in higher polyp counts in the small intestine and colon. Interestingly, intestine polyps that developed in the absence of MALAT1 were smaller in size. These findings highlight the unexpected bivalent role of MALAT1 in restricting and promoting cancer progression at different disease stages. Among the 30 MALAT1-targets shared by both the small intestine and colon, ZNF638 and SENP8 levels are predictive of colon adenoma patient overall survival and disease-free survival. Genomic assays further revealed that MALAT1 modulates intestinal target expression and splicing through both direct and indirect mechanisms. This study expands the role of lncRNAs in regulating intestine homeostasis, microbial communities, and cancer pathogenesis.