Willingness to accept and participate in a Microsporidia MB-based mosquito release strategy: a community-based rapid assessment in western Kenya.

BACKGROUND: Microsporidia MB, an endosymbiont naturally found in Anopheles mosquitoes inhibits transmission of Plasmodium and is a promising candidate for a transmission-blocking strategy that may involve mosquito release. A rapid assessment was carried out to develop insight into sociodemographic factors, public health concerns, and malaria awareness, management, and prevention practices with the willingness to accept and participate in Microsporidia MB-based transmission-blocking strategy to develop an informed stakeholder engagement process. METHODS: The assessment consisted of a survey conducted in two communities in western Kenya that involved administering a questionnaire consisting of structured, semi-structured, and open questions to 8108 household heads. RESULTS: There was an overall high level of willingness to accept (81%) and participate in the implementation of the strategy (96%). Although the willingness to accept was similar in both communities, Ombeyi community was more willing to participate (OR 22, 95% CI 13-36). Women were less willing to accept (OR 0.8, 95% CI 0.7-0.9) compared to men due to fear of increased mosquito bites near homes. Household heads with incomplete primary education were more willing to accept (OR 1.6, 95% CI 01.2-2.2) compared to those educated to primary level or higher. Perceiving malaria as a moderate or low public health issue was also associated with a lower willingness to accept and participate. Experience of > 3 malaria cases in the family over the last six months and knowledge that malaria is transmitted by only mosquito bites, increased the willingness to accept but reduced the willingness to participate. Awareness of malaria control methods based on mosquitoes that cannot transmit malaria increases the willingness to participate. CONCLUSION: The study showed a high level of willingness to accept and participate in a Microsporidia MB-based strategy in the community, which is influenced by several factors such as community, disease risk perception, gender, education level, knowledge, and experience of malaria. Further research will need to focus on understanding the concerns of women, educated, and employed community members, and factors that contribute to the lower disease risk perception. This improved understanding will lead to the development of an effective communication strategy.

Localization and tissue tropism of the symbiont Microsporidia MB in the germ line and somatic tissues of Anopheles arabiensis.

IMPORTANCE: Microsporidia MB is a symbiont with a strong malaria transmission-blocking phenotype in Anopheles arabiensis. It spreads in mosquito populations through mother-to-offspring and sexual transmission. The ability of Microsporidia MB to block Plasmodium transmission, together with its ability to spread within Anopheles populations and its avirulence to the host, makes it a very attractive candidate for developing a key strategy to stop malaria transmissions. Here, we report tissue tropism and localization patterns of Microsporidia MB, which are relevant to its transmission. We find that Microsporidia MB accumulates in Anopheles arabiensis tissues, linked to its sexual and vertical transmission. Its prevalence and intensity in the tissues over the mosquito life cycle suggest adaptation to maximize transmission and avirulence in Anopheles arabiensis. These findings provide the foundation for understanding the factors that may affect Microsporidia MB transmission efficiency. This will contribute to the development of strategies to maximize Microsporidia MB transmission to establish and sustain a high prevalence of the symbiont in Anopheles mosquito populations for malaria transmission blocking.

Friend or Foe: Symbiotic Bacteria in Bactrocera dorsalis-Parasitoid Associations.

Parasitoids are promising biocontrol agents of the devastating fruit fly, Bactrocera dorsalis. However, parasitoid performance is a function of several factors, including host-associated symbiotic bacteria. Providencia alcalifaciens, Citrobacter freundii, and Lactococcus lactis are among the symbiotic bacteria commonly associated with B. dorsalis, and they influence the eco-physiological functioning of this pest. However, whether these bacteria influence the interaction between this pest and its parasitoids is unknown. This study sought to elucidate the nature of the interaction of the parasitoids, Fopius arisanus, Diachasmimorpha longicaudata, and Psyttlia cosyrae with B. dorsalis as mediated by symbiotic bacteria. Three types of fly lines were used: axenic, symbiotic, and bacteria-mono-associated (Lactococcus lactis, Providencia alcalifaciens, and Citrobacter freundii). The suitable stages of each fly line were exposed to the respective parasitoid species and reared until the emergence of adult flies/parasitoids. Thereafter, data on the emergence and parasitoid fitness traits were recorded. No wasps emerged from the fly lines exposed to P. cosyrae. The highest emergence of F. arisanus and D. longicaudata was recorded in the L. lactis fly lines. The parasitoid progeny from the L. lactis and P. alcalifaciens fly lines had the longest developmental time and the largest body size. Conversely, parasitoid fecundity was significantly lower in the L. lactis lines, whereas the P. alcalifaciens lines significantly improved fecundity. These results elucidate some effects of bacterial symbionts on host-parasitoid interactions and their potential in enhancing parasitoid-oriented management strategies against B. dorsalis.

Influence of inoculated gut bacteria on the development of Bactrocera dorsalis and on its susceptibility to the entomopathogenic fungus, Metarhizium anisopliae.

BACKGROUND: Symbiotic interactions between insects and bacteria have been associated with a vast variety of physiological, ecological and evolutionary consequences for the host. A wide range of bacterial communities have been found in association with the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), an important pest of cultivated fruit in most regions of the world. We evaluated the diversity of gut bacteria in B. dorsalis specimens from several populations in Kenya and investigated the roles of individual bacterial isolates in the development of axenic (germ-free) B. dorsalis fly lines and their responses to the entomopathogenic fungus, Metarhizium anisopliae. RESULTS: We sequenced 16S rRNA to evaluate microbiomes and coupled this with bacterial culturing. Bacterial isolates were mono-associated with axenic B. dorsalis embryos. The shortest embryonic development period was recorded in flies with an intact gut microbiome while the longest period was recorded in axenic fly lines. Similarly, larval development was shortest in flies with an intact gut microbiome, in addition to flies inoculated with Providencia alcalifaciens. Adult B. dorsalis flies emerging from embryos that had been mono-associated with a strain of Lactococcus lactis had decreased survival when challenged with a standard dosage of M. anisopliae ICIPE69 conidia. However, there were no differences in survival between the germ-free lines and flies with an intact microbiome. CONCLUSIONS: These findings will contribute to the selection of probiotics used in artificial diets for B. dorsalis rearing and the development of improved integrated pest management strategies based on entomopathogenic fungi.

Diversity of fall armyworm, Spodoptera frugiperda and their gut bacterial community in Kenya.

BACKGROUND: The invasive fall armyworm, Spodoptera frugiperda (J.E. Smith) is a polyphagous pest that causes widespread damage particularly to maize and sorghum in Africa. The microbiome associated with S. frugiperda could play a role in the insects' success and adaptability. However, bacterial communities in S. frugiperda remain poorly studied. METHODS: We investigated the composition, abundance and diversity of microbiomes associated with larval and adult specimens of S. frugiperda collected from four maize growing regions in Kenya through high throughput sequencing of the bacterial 16S rRNA gene. The population structure of S. frugiperda in Kenya was assessed through amplification of the mitochondrial cytochrome oxidase subunit I gene. RESULTS: We identified Proteobacteria and Firmicutes as the most dominant bacterial phyla and lesser proportions of Bacteroidetes and Actinobacteria. We also observed differences in bacterial microbiome diversity between larvae and adults that are a likely indication that some prominent larval bacterial groups are lost during metamorphosis. However, several bacterial groups were found in both adults and larvae suggesting that they are transmitted across developmental stages. Reads corresponding to several known entomopathogenic bacterial clades as well as the fungal entomopathogen, Metarhizium rileyi, were observed. Mitochondrial DNA haplotyping of the S. frugiperda population in Kenya indicated the presence of both "Rice" and "Corn" strains, with a higher prevalence of the "Rice" strain.

Unexpected Diversity of Wolbachia Associated with Bactrocera dorsalis (Diptera: Tephritidae) in Africa.

Bactrocera dorsalis (Hendel) is an important pest of fruit-bearing plants in many countries worldwide. In Africa, this pest has spread rapidly and has become widely established since the first invasion report in 2003. Wolbachia is a vertically transmitted endosymbiont that can significantly influence aspects of the biology and, in particular, the reproduction of its host. In this study, we screened B. dorsalis specimens collected from several locations in Africa between 2005 and 2017 for Wolbachia using a PCR-based assay to target the Wolbachia surface protein wsp. Of the 357 individuals tested, 10 were positive for Wolbachia using the wsp assay. We identified four strains of Wolbachia infecting two B. dorsalis mitochondrial haplotypes. We found no strict association between the infecting strain and host haplotype, with one strain being present in two different host haplotypes. All the detected strains belonged to Super Group B Wolbachia and did not match any strains reported previously in B. dorsalis in Asia. These findings indicate that diverse Wolbachia infections are present in invasive populations of B. dorsalis.

Endometrial histopathology in patients with laparoscopic proven salpingitis and HIV-1 infection.

STUDY OBJECTIVE: To identify sensitive and specific histological criteria for endometritis in women with laparoscopically-confirmed acute salpingitis. METHODS: Women, age 18-40 years of age presenting with complaints of lower abdominal pain ≤2 weeks and no antibiotics use in past two weeks, were enrolled. They underwent clinical examination, screening for HIV; other sexually transmitted infections plus endometrial biopsy sampling for histopathology. Diagnostic laparoscopy confirmed the diagnosis of acute salpingitis. Controls were women undergoing tubal ligation and HIV-1 infected women asymptomatic for genital tract infection. RESULTS: Of 125 women with laparoscopically-confirmed salpingitis, 38% were HIV-1 seropositive. Nineteen HIV-1 negative controls were recruited. For the diagnosis of endometritis, ≥1 plasma cells (PC) and ≥3 polymorphonuclear lymphocytes (PMN) per HPF in the endometrium had a sensitivity of 74% for HIV-1-seropositive, 63% for HIV-1-seronegative women with a specificity of 75% and positive predictive value of 85% regardless of HIV-1-infection for predicting moderate to severe salpingitis. For HIV-1-seronegative women with mild salpingitis, ≥1 PC and ≥3 PMN had a sensitivity of 16% and a PPV of 57%. CONCLUSION: Endometrial histology, did not perform well as a surrogate marker for moderate to severe salpingitis, and failed as a surrogate marker for mild salpingitis.

Effect of human immunodeficiency virus-1 infection on treatment outcome of acute salpingitis.

OBJECTIVE: To examine the effect of human immunodeficiency virus (HIV)-1 infection on treatment outcome of laparoscopically verified acute salpingitis. METHODS: Women aged 18-40 years with laparoscopically verified acute salpingitis received antibiotic therapy that included cefotetan 2 g intravenously and doxycycline 100 mg orally every 12 hours and laparoscopically guided drainage of tuboovarian abscesses of 4 cm or more. Clinical investigators blinded to HIV-1 serostatus used predetermined clinical criteria, including calculation of a clinical severity score and a standard treatment protocol to assess response to therapy. RESULTS: Of the 140 women with laparoscopically confirmed acute salpingitis, 61 (44%) women had mild, 38 (27%) had moderate, and 41 (29%) had severe disease (ie, pyosalpinx, tuboovarian abscesses, or both). Fifty-three (38%) were HIV-1-infected. Severe disease was more common in HIV-1-infected in comparison with HIV-1-uninfected women (20 [38%] compared with 21 [24%], P = .02). Defined as time of hospital discharge or 75% or more reduction in baseline clinical severity score, HIV-1-infected women with severe (6 days [4-16] compared with 5 days [3-9], P = .09) but not those with either mild (4 days [2-6] compared with 4 days [2-6] P = .4) or moderate salpingitis (4 days [3-7] compared with 4 days [3-6] P = .32) tended to take longer to meet criteria for clinical improvement. The need for intravenous clindamycin or additional surgery was not different in HIV-1-infected and uninfected cases (15 [28%] compared with 18 [21%], P = .3). CONCLUSION: Although HIV-1 infection may prolong hospitalization in women with severe salpingitis, all women hospitalized with acute salpingitis responded promptly to antibiotic therapy and surgical drainage regardless of HIV-1 infection status. LEVEL OF EVIDENCE: II-2.