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Results for “Vectorial competence”

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PubMed2026

Plasmodium falciparum sporozoite loads in Anopheles gambiae s.l. across agro-ecological zones of Benin: a cross-sectional field study.

BACKGROUND: Malaria transmission depends critically on the vectorial competence of Anopheles mosquitoes, which is partly reflected by the quantity of infectious Plasmodium falciparum forms harboured in the salivary glands. Whether agro-ecological heterogeneity and vector species identity modulate this parasite burden remains poorly characterized in Benin. METHODS: Anopheles gambiae s.l. were collected by Human Landing Catch across 12 localities spanning 7 agro-ecological zones in Benin during August-October 2022. Species were identified by SINE-PCR. P. falciparum infection was assessed by circumsporozoite protein (CSP) ELISA, and sporozoite load was quantified in positive head-thorax preparations by real-time PCR targeting the plasmepsin gene (NZYTech kit, ref. MD 02411). Statistical comparisons across agro-ecological zones (within each species) used the Kruskal-Wallis test, and the two-species comparison used the Mann-Whitney U test, in R v4.4.1. RESULTS: A total of 1,355 individuals were molecularly analyzed for species identification. Of 3,021 mosquitoes collected, these 1,355 yielded 858 An. coluzzii (63.32%), 489 An. gambiae (36.09%), and 8 An. arabiensis (0.59%). The overall sporozoite index was 5.98% (95% CI 4.8-7.4%), ranging from 0% in Cotonou and Parakou to 16.19% in Boukoumbé. No significant inter-zonal variation in sporozoite load was detected in either An. coluzzii (Kruskal-Wallis: H = 5.79, df = 3, p = 0.122) or An. gambiae (H = 3.25, df = 2, p = 0.197). However, An. coluzzii carried a significantly higher sporozoite burden than An. gambiae (Mann-Whitney U = 381, p < 0.001). CONCLUSIONS: Broad agro-ecological zone categories were not associated with detectable differences in individual P. falciparum sporozoite load in the principal malaria vectors of Benin. Anopheles coluzzii carried a significantly higher sporozoite burden than An. gambiae, indicating species-level differences in parasite permissiveness that merit further investigation.

Anopheles coluzzii↗

PubMed1978

A multidisciplinary study on bancroftian filariasis in Jakarta.

A study on bancroftian filariasis in Jakarta has indicated that one person in one year could be exposed to 223,000 bites of Culex pipens fatigans and to 1,941 infective-stage larvae of Wuchereria bancrofti. Blood surveys with 20 mm3 samples revealed a microfilaria rate of 6%. Although some cases of hydrocele (4% of 272 males examined) were found, there was little evidence of severe filarial disease in either males or females. Amongst wild-caught mosquitoes only 0.3% contained infective larvae, but much higher levels of vectorial competence were established under laboratory conditions. High daily vector mortality (30%) coupled with noticeable improvements in standards of living could have been important factors preventing an increase in endemicity.

Adolescent↗

PubMed1992

Bone and calcium homeostasis.

The principal repository of calcium is bone. Calcium enters bone largely via the trabeculae, with the rate of calcium clearance by bone approximating 50 percent. Calcium enters bone as an ion in solution, but undergoes a phase change to a solid as soon as in contact with the bone surfaces. Calcium removal from and redistribution in bone is mediated by the bone cells, principally osteoblasts and osteoclasts. Calcium enters the body via intestinal absorption, a transport process that is the vectorial result of a saturable and an non-saturable step. Calcium leaves the body in the urine and stool, with a circulating calcium ion having one chance in about four of being lost via excretion. Ions like lead can compete with calcium at the sites of calcium deposition and transport. Their rate in the body should therefore parallel that of calcium, but may be modified by differing binding affinities or interactions with specific sites and molecules.

Animals↗

PubMed1992

WGA-binding, mucin glycoproteins protect the apical cell surface of mouse uterine epithelial cells.

Expression of apical cell surface proteins and glycoproteins was examined in polarized primary cultures of mouse uterine epithelial cells (UEC). Lectin-gold cytochemistry revealed that wheat germ agglutinin (WGA) bound specifically to the components of the apical glycocalyx as well as intracellular vesicles. Double labeling with the pH sensitive dye 3-(2,4-dinitroanilino)-3'amino-N-methyldipropylamine (DAMP) demonstrated the acidic nature of the WGA-staining intracellular vesicles. The enzymatic and chemical sensitivities of the WGA binding sites on the apical cell surface were monitored both by WGA-gold staining as well as by 125I-WGA binding assays. In thin sections, a large fraction of these sites were removed by pronase; however, application of a wide variety of proteases, glycosidases, or chemical treatments to the apical surface of intact UEC failed to reduce WGA binding. In no case did treatments designed to remove sialic acids reduce 125I-WGA binding more than 12%. In contrast, endo-beta-galactosidase as well as a combination of beta-galactosidase with beta-hexosaminidase succeeded in removing 28% and 77% of these sites, respectively. These studies suggested that the majority of the apically disposed WGA binding sites involved N-acetylglucosamine residues rather than sialic acids and included lactosaminoglycans. Many of the proteins detected at the apical cell surface by lactoperoxidase-catalyzed radioiodination were WGA-binding glycoproteins. A major class of these glycoproteins displayed Mr > 200 kDa by SDS-PAGE and was heavily labeled metabolically by 3H-glucosamine or by vectorial labeling at the apical cell surface with galactosyl transferase and UDP-3H-galactose. Analyses of the 3H-labeled oligosaccharides labeled by either procedure indicated that a large fraction of the apically disposed WGA-binding oligosaccharides consisted of neutral, O-linked mucin-type structures with median MW of approximately 1,500. Oligosaccharides in this fraction were partially (15%) sensitive to endo-beta-galactosidase digestion and bound to Datura stramonium agglutinin (68%), demonstrating the presence of lactosaminoglycan sequences. UEC were an extremely effective barrier to attachment or invasion by either a highly invasive melanoma cell line, B16-BL6, or implantation-competent mouse blastocysts. In contrast, neither uterine stromal cells nor a non-polarizing UEC cell line, RL95, prevented B16-BL6 attachment.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗