The objective of this study was to determine the association between mycotoxins and the quality of spermatozoa in Nigeria. We designed a prospective case-control study involving 136 men diagnosed with reduced sperm count and quality in five infertility clinics in southwest Nigeria and 154 normal fertile controls. Sperm analysis was conducted in accordance with the recommendations of the World Health OrganizationWHO, while Liquid Chromatography–Mass Spectrometry was used to assay three metabolites of mycotoxins (zearalenone, ochratoxin A, and deoxyvinelol) in the urine samples of cases and controls. The data were analysed with descriptive statistics and non-parametric linear regression. The results showed no overall significant difference in levels of these metabolites between the cases and control groups. In contrast, higher levels of zearalenone and ochratoxin A significantly decreased sperm motility in the cases. Similarly, an increase in the level of ochratoxin A decreased sperm morphology in the unadjusted model in the cases. We conclude that exposure to mycotoxins reduces the quality of spermatozoa (motility and morphology) in Nigerian men but may have no effect on sperm count. Efforts to reduce the exposure of men to mycotoxins are important interventions to improve sperm quality and reduce the prevalence of male infertility in the country.

Irregular use of antibiotics is widespread in Nigeria, which has been reported to be associated with the prevalence of antibiotic resistance. As antibiotics have been reported to be associated with declining male infertility in animal models, we investigated the association between exposure to antibiotics and sperm quality. The study was a prospective case–control study involving 136 infertile men and 154 fertile men recruited from five hospitals in southern Nigeria. Semen analysis was carried out, while Liquid Chromatography Mass Spectrometry was used to assay for various antibiotics in urinary samples. Three antibiotics showed an independent association with sperm quality in the regression analysis. Urinary ampicillin was associated with more than a 3 mL decline in sperm count in the cases, with no significant effects shown in the control group. Similarly, a significant association of urinary chloramphenicol with sperm motility and sperm morphology was shown in cases of infertility. In contrast, an independent association of urinary tetracycline with increased sperm motility in men with infertility was found, but no significant association was shown in fertile men. We conclude that urinary antibiotics—ampicillin, tetracycline, and chloramphenicol—may be associated with varying sperm characteristics and sperm quality in Nigerian men.

The salivary gland (SG) is the final barrier for Plasmodium transmission to humans but remains comparatively understudied relative to the midgut microbiome. This review synthesizes current knowledge on SG microbiome acquisition routes, composition, and functional significance. Acquisition may occur via larval filter feeding, vertical (egg smearing), transstadial, or horizontal transmission during blood feeding, though their relative contributions are unknown. Compositional studies show Gram-negative genera Serratia , Elizabethkingia , Acinetobacter , Pseudomonas , and Asaia predominate; Plasmodium infection correlates with increased Serratia and decreased Elizabethkingia abundance. While immune-related genes (e.g., cecropins, defensin, GNBP, SRPN6) expressed in the SG may be modulated by resident bacteria, direct evidence of their effect on sporozoite invasion remains lacking. Gram-negative bacteria trigger Toll, Imd, and JAK-STAT pathways, but emerging evidence suggests the SG may mount a distinct, locally independent immune response compared to the systemic pathway. Paratransgenesis using Asaia shows promise, yet SG-targeted effector delivery remains untested. Ecological pressures common in West Africa, including agricultural pesticides, insecticide resistance, and larval water contamination, may influence mosquito-associated bacteria, but no studies explicitly link these to the SG microbiome. Significant knowledge gaps persist, notably the absence of field studies in high-burden regions like Nigeria and the lack of experimental manipulation to establish causality. Addressing these priorities is critical to determine whether the SG microbiome can be exploited as a transmission-blocking target.

Malaria continues to be a significant health challenge worldwide, causing 282 million cases and 610,000 deaths in 2024, especially in sub-Saharan