Knowledge and attitudes in the prevention of vertical transmission of HIV in referral hospitals.

Background: Prevention of HIV vertical transmission programmes (VTPs) in South Africa has decreased paediatric HIV. These programmes require integration in referral hospitals. Objectives: To determine knowledge of and attitudes to the national VTP guidelines in staff from Obstetric and Paediatric disciplines at two referral hospitals. Method: Using a cross-sectional design, a questionnaire to assess knowledge of the guidelines and attitudes (awareness, ease-of-use and non-silo practice, measuring integrated practice) was developed and validated locally. Using standard statistical analyses, data from these questionnaires were used to draw comparisons and determine factors associated with knowledge and attitudes. Results: Of the 249 participants, 138 (55.4%) were in obstetrics, 125 (50.2%) were nurses, and 168 (67.5%) self-identified as junior staff. Knowledge scores were good, median score (Q1-Q3) was 91.7% (79.1-95.8), and higher in those who had discipline-specific training (P = 0.003). Junior staff (P = 0.002) had higher knowledge levels than senior staff. Most (80%) found the guidelines easy to use and had good awareness, which correlated with knowledge and training. Gaps included understanding of antenatal testing of HIV-negative women and timelines for neonatal HIV testing. Staff scored poorly on integrated practice; the median score (Q1-Q3) was 50% (33.3-58.3), which was inversely correlated with knowledge (r= -0.146, n = 249, P = 0.022). Conclusion: Staff in referral hospitals appear to be practising within silos when implementing VTPs, and this may result in failures to ensure integrated practice. Regularised interdisciplinary and interprofessional training may be important to ensure the integrated implementation of VTPs in referral hospitals.

Delineating dengue risk zones in Jaipur: An interdisciplinary approach to inform public health strategies.

Dengue fever (DF) is a pervasive public health concern in tropical climates, with densely populated regions, such as India, disproportionately affected. Addressing this issue requires a multifaceted understanding of the environmental and sociocultural factors that contribute to the risk of dengue infection. This study aimed to identify high-risk zones for DF in Jaipur, Rajasthan, India, by integrating physical, demographic, and epidemiological data in a comprehensive risk analysis framework. We investigated environmental variables, such as soil type and plant cover, to characterize the potential habitats of Aedes aegypti, the primary dengue vector. Concurrently, demographic metrics were evaluated to assess the population's susceptibility to dengue outbreaks. High-risk areas were systematically identified through a comparative analysis that integrated population density and incidence rates per ward. The results revealed a significant correlation between high population density and an increased risk of dengue, predominantly facilitated by vertical transmission. Spatially, these high-risk zones are concentrated in the northern and southern sectors of Jaipur, with the northern and southwestern wards exhibiting the most acute risk profiles. This study underscores the importance of targeted public health interventions and vaccination campaigns in vulnerable areas. It further lays the groundwork for future research to evaluate the effectiveness of such interventions, thereby contributing to the development of robust evidence-based strategies for dengue risk mitigation.

Prevention of vertical transmission of hepatitis B: A retrospective review of a 5-year maternal-infant cohort in London.

AIMS: The World Health Organization (WHO) estimates that 3.5% of the population live with hepatitis B virus (HBV); migrants to Europe are disproportionately affected. UK birth dose HBV vaccination is limited to infants born to those living with HBV (LWHBV). High-risk infants (high maternal infectivity, low birthweight) also receive HBV immunoglobulin (HBIG). The Family Hepatitis Clinic follows infants and those LWHBV working towards WHO goals of combating viral hepatitis by 2030. METHODS: A trust-wide electronic note review of outcomes for infants born to those LWHBV (2016-2020). RESULTS: Two hundred and eighty-three infants, 134 (47%) females, born to those LWHBV were referred. Two hundred and thirty-one (82%) attended follow-up with a vertical transmission rate of 0%. Twenty (7%) individuals LWHBV received tenofovir disoproxil fumerate in pregnancy; median viral load (VL) at initiation 125 416 376 DNA IU/mL, one having birth VL. Twenty-eight (10%) infants were stratified as high risk and all received HBIG and birth dose vaccination with 9 (32%) subsequently lost to follow-up, compared to 48 (19%) low-risk infants. 267/283 (94%) had birth dose vaccination documented and 206/283 (73%) received at least four vaccine doses. 215/283 (76%) infants had serology by 24 months; 17 (6%) with suboptimal vaccine responses: hepatitis B surface antibody <100 IU/mL. Serology before 18 months resulted in higher rates of maternal hepatitis B core antibody detection (15% vs. 3%). CONCLUSION: Prevention of vertical transmission of HBV was universal in those attending, although high-risk infants were more likely lost to follow up. HBV post-vaccine serological protection was comparable with national data from 2021 (77% >4 doses, 77% HBsAb >100).

Transmission of mycoviruses: new possibilities.

Mycoviruses are viruses that infect fungi. In recent years, an increasing number of mycoviruses have been reported in a wide array of fungi. With the growing interest of scientists and society in reducing the use of agrochemicals, the debate about mycoviruses as an effective next-generation biocontrol has regained momentum. Mycoviruses can have profound effects on the host phenotype, although most viruses have neutral or no effect. We speculate that understanding multiple transmission modes of mycoviruses is central to unraveling the viral ecology and their function in regulating fungal populations. Unlike plant virus transmission via vegetative plant parts, seeds, pollen, or vectors, a widely held view is that mycoviruses are transmitted via vertical routes and only under special circumstances horizontally via hyphal contact depending on the vegetative compatibility groups (i.e., the ability of different fungal strains to undergo hyphal fusion). However, this view has been challenged over the past decades, as new possible transmission routes of mycoviruses are beginning to unravel. In this perspective, we discuss emerging studies with evidence suggesting that such novel routes of mycovirus transmission exist and are pertinent to understanding the full picture of mycovirus ecology and evolution.

Microbiome of two adult tick species and their laboratory-reared offspring shows intra- and inter-species differences.

Tick-borne pathogens are a significant threat to human and animal health. Exposing the microbial composition of ticks elucidates their potential role in transmitting pathogens and causing disease as well as uncovering their potential interaction with the hosting tick. Our study focused on characterizing the tick microbiome of adult females and their lab-reared larval offspring of two prevalent tick species found on dogs in Nigeria [Rhipicephalus sanguineus s.l. tropical lineage (R. linnaei) and Haemaphysalis leachi]. We investigated the relative phyla abundance, the alpha and beta diversities of microbial communities comparing tick species, and different development stages (adults versus larvae). To the best of our knowledge, this is the first analysis on H. leachi microbiome described from West Africa. Our findings revealed a diverse microbiome with significant differences across species and their developmental stages, highlighting the dominance of the Proteobacteria phylum, followed by Firmicutes and Actinobacteriota. In contrast to H. leachi, for R. linnaei we observed significant differences in the alpha and beta diversities of the microbiome of larvae and adult females. Predominant bacterial genera were identified in R. linnaei, particularly Arsenophonus and Coxiella, which showed increased abundance in adult ticks. In H. leachi, other predominant genera were detected, including Sphingomonas, Comamonas, and Williamsia. Our results contribute to the understanding of microbiome dynamics within ticks and offers insights of tick physiology for addressing public health concerns and developing effective strategies for pathogen control.

An interprofessional model of care for adolescents with perinatal HIV: A qualitative study.

Background and Aims: The number of perinatally HIV-infected adolescents (PHIVA) is increasing however many health care systems are not prepared for this population and their health challenges, specifically a model of care (MoC) is lacking. Thus the objective of this study was to develop and propose a MoC for PHIVA. Methods: Through a qualitative study design, a MoC was developed and ratified with two focus groups, consisting of PHIVA and healthcare professionals. Results: Seven participants were included in each focus group and the following themes were developed: relatable attributes; missing components; implementation and suggestions. Changes were made to the drafts of the MoC in response to the focus group results, leading to the finalisation of a MoC for PHIVA. The MoC focused on the importance of interprofessional health care and addressed the physical sequelae that PHIVA are likely to encounter. A schematic of the MoC was created for the use in general public education. Conclusion: It is important that healthcare facilities are equipped to handle the specific needs of PHIVA. The interprofessional MoC developed in this study helps to address the requirements of this population.

Highly diverse microbial community of regenerated seedlings reveals the high capacity of the bulb in lily, Lilium brownii.

Lily bulbs, which have both nutrient storage and reproductive functions, are a representative group of plants for studying the maintenance and transfer of plant-associated microbiomes. In this study, a comparison of the microbial composition of bulbs and their regenerated seedlings cultured under aseptic conditions, as well as subcultured seedlings that succeeded five times, was examined by amplicon sequencing. A total of 62 bacterial taxa and 56 fungal taxa were found to be transferred to the 5th generation in seedlings, which are the core microbiome of lily. After the regeneration of seedlings from bulbs, there was a significant increase in the number of detectable microbial species, and after 1, 3, and 5 successive generations, there was a decrease in the number of detectable species. Interestingly, some "new" microorganisms appeared in each generation of samples; for instance, 167 and 168 bacterial operational taxonomic units (OTUs) in the 3rd and 5th generations of seedlings that were not detected in either bulbs or seedlings of the previous two generations. These results suggest that bulbs can maintain a high diversity of microorganisms, including some with ultra-low abundance, and have a high transfer capacity to tuck shoots through continuous subculture. The diversity and maintenance of the microbiome can provide the necessary microbial reservoir support for regenerating seedlings. This habit of maintaining low abundance and high diversity may be biologically and ecologically critical for maintaining microbiome stability and function due to the sequestration nature of the plant.

Understanding Women's Preferences for Prevention of Mother-to-Child HIV Transmission Services in Kenya.

Background and Objective: Understanding the preferences of women living with HIV (WLH) for the prevention of mother-to-child HIV transmission (PMTCT) services is important to ensure such services are person-centered. Methods: From April to December 2022, we surveyed pregnant and postpartum WLH enrolled at five health facilities in western Kenya to understand their preferences for PMTCT services. WLH were stratified based on the timing of HIV diagnosis: known HIV-positive (KHP; before antenatal clinic [ANC] enrollment), newly HIV-positive (NHP; on/after ANC enrollment). Multivariable logistic regression was used to determine associations between various service preferences and NHP (vs. KHP) status, controlling for age, facility, gravidity, retention status, and pregnancy status. Results: Among 250 participants (median age 31 years, 31% NHP, 69% KHP), 93% preferred integrated versus non-integrated HIV and maternal-child health (MCH) services; 37% preferred male partners attend at least one ANC appointment (vs. no attendance/no preference); 54% preferred support groups (vs. no groups; 96% preferred facility - over community-based groups); and, preferences for groups was lower among NHP (42%) versus KHP (60%). NHP had lower odds of preferring support groups versus KHP (aOR 0.45, 95% CI 0.25-0.82), but not the other services. Conclusion and Global Health Implications: Integrated services were highly preferred by WLH, supporting the current PMTCT service model in Kenya. Further research is needed to explore the implementation of facility-based support groups for WLH as well as the reasons underlying women's preferences.

Discovery of Epichloë as novel endophytes of Psathyrostachys lanuginosa in China and their alkaloid profiling.

The Epichloë genus represents a significant group of above-ground endophytes extensively researched for their potential applications in agriculture and ecology. Additionally, Epichloë species synthesize bioactive alkaloids, which generally cause health problems in livestock and have detrimental effects on the performance of insect herbivores. Psathyrostachys lanuginosa serves as a valuable forage grass for livestock owing to its high nutritional value and resilience in adverse environmental conditions. Nevertheless, to date, no reports have documented Epichloë as endophytes of P. lanuginosa. In this study, four strains (PF5, PF9, QG2, and QG4) were isolated and identified through morphological, molecular, and phylogenetic analyses as endophytes of P. lanuginosa. Morphological analysis indicated colony characteristics and conidia features consistent with symbiotic Epichloë, with no significant differences observed in growth rates or conidia dimensions among the four strains. Phylogenetic analysis confirmed all strains as E. bromicola. Additionally, alkaloid biosynthetic genes were detected, revealing differences in the potential synthesis of peramine and indole diterpenoid alkaloids among strains from different geographic origins. However, all four E. bromicola strains exhibited similar potential for synthesizing ergot alkaloids, but not loline alkaloids. Overall, this study identified P. lanuginosa as a novel host for E. bromicola and provided insights into the alkaloid profiles of these strains, laying a solid foundation for the scientific and rational utilization of Epichloë resources.

Impact of SARS-CoV-2 infection during pregnancy on the placenta and fetus.

Pregnant people and their fetuses are vulnerable to adverse health outcomes from coronavirus 2019 disease (COVID-19) due to infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has been associated with higher rates of maternal mortality, preterm birth, and stillbirth. While SARS-CoV-2 infection of the placenta and vertical transmission is rare, this may be due to the typically longer time interval between maternal infection and testing of the placenta and neonate. Placental injury is evident in cases of SARS-CoV-2-associated stillbirth with massive perivillous fibrin deposition, chronic histiocytic intervillositis, and trophoblast necrosis. Maternal COVID-19 can also polarize fetal immunity, which may have long-term effects on neurodevelopment. Although the COVID-19 pandemic continues to evolve, the impact of emerging SARS-CoV-2 variants on placental and perinatal injury/mortality remains concerning for maternal and perinatal health. Here, we highlight the impact of COVID-19 on the placenta and fetus and remaining knowledge gaps.

Cancrum oris and hemiparesis in a young female patient-a case report.

Key Clinical Message: Noma is still around today and can be deadly if ignored. Prompt identification and comprehensive care are essential for averting permanent impairments and disfigurements. Abstract: Noma is a rapid developing orofacial gangrene and a disabling disease that primarily affects young children who live in dangerous conditions. Underlying diseases such as HIV/AIDS and malnutrition can enhance the likelihood of Noma's emergence. This is a case of a 9-year-old girl patient who arrived malnourished and with an ulcerating communicating right mandibular soft tissue lesion as well as right hemiparesis which had an acute onset. The patient was likewise HIV positive discovered upon admission, possibly as a result of vertical transmission, and was an ART (antiretroviral therapy) treatment naive patient. A holistic treatment plan was installed and a positive clinical response was observed. Early treatment is key in Noma management.

Reduction in vertical transmission rate of bean common mosaic virus in bee-pollinated common bean plants.

Vertical transmission, the transfer of pathogens across generations, is a critical mechanism for the persistence of plant viruses. The transmission mechanisms are diverse, involving direct invasion through the suspensor and virus entry into developing gametes before achieving symplastic isolation. Despite the progress in understanding vertical virus transmission, the environmental factors influencing this process remain largely unexplored. We investigated the complex interplay between vertical transmission of plant viruses and pollination dynamics, focusing on common bean (Phaseolus vulgaris). The intricate relationship between plants and pollinators, especially bees, is essential for global ecosystems and crop productivity. We explored the impact of virus infection on seed transmission rates, with a particular emphasis on bean common mosaic virus (BCMV), bean common mosaic necrosis virus (BCMNV), and cucumber mosaic virus (CMV). Under controlled growth conditions, BCMNV exhibited the highest seed transmission rate, followed by BCMV and CMV. Notably, in the field, bee-pollinated BCMV-infected plants showed a reduced transmission rate compared to self-pollinated plants. This highlights the influence of pollinators on virus transmission dynamics. The findings demonstrate the virus-specific nature of seed transmission and underscore the importance of considering environmental factors, such as pollination, in understanding and managing plant virus spread.

Cell Culture Evaluation Hints Widely Available HIV Drugs Are Primed for Success if Repurposed for HTLV-1 Prevention.

With an estimated 10 million people infected, the deltaretrovirus human T-cell lymphotropic virus type 1 (HTLV-1) is the second most prevalent pathogenic retrovirus in humans after HIV-1. Like HIV-1, HTLV-1 overwhelmingly persists in a host via a reservoir of latently infected CD4+ T cells. Although most patients are asymptomatic, HTLV-1-associated pathologies are often debilitating and include adult T-cell leukaemia/lymphoma (ATLL), which presents in mature adulthood and is associated with poor prognosis with short overall survival despite treatment. Curiously, the strongest indicator for the development of ATLL is the acquisition of HTLV-1 through breastfeeding. There are no therapeutic or preventative regimens for HTLV-1. However, antiretrovirals (ARVs), which target the essential retrovirus enzymes, have been developed for and transformed HIV therapy. As the architectures of retroviral enzyme active sites are highly conserved, some HIV-specific compounds are active against HTLV-1. Here, we expand on our work, which showed that integrase strand transfer inhibitors (INSTIs) and some nucleoside reverse transcriptase inhibitors (NRTIs) block HTLV-1 transmission in cell culture. Specifically, we find that dolutegravir, the INSTI currently recommended as the basis of all new combination antiretroviral therapy prescriptions, and the latest prodrug formula of the NRTI tenofovir, tenofovir alafenamide, also potently inhibit HTLV-1 infection. Our results, if replicated in a clinical setting, could see transmission rates of HTLV-1 and future caseloads of HTLV-1-associated pathologies like ATLL dramatically cut via the simple repurposing of already widely available HIV pills in HTLV-1 endemic areas. Considering our findings with the old medical saying "it is better to prevent than cure", we highly recommend the inclusion of INSTIs and tenofovir prodrugs in upcoming HTLV-1 clinical trials as potential prophylactics.

Detection and genetic characterization of chicken astrovirus and Avian Nephritis virus from hatchery to farm.

Astroviruses are an emerging hazard in hatchery management, and they are responsible for great economic losses in poultry farms worldwide. Chicken astrovirus (CAstV) and Avian Nephritis virus (ANV) are involved in hatching decrease mainly due to embryo deaths, pale and runted chicks too weak to hatch. Hatchery diseases occur through direct egg infection or through vertical transmission. However, the specific role of astroviruses in these diseases is still largely unknown. To elucidate this question, a high-quality Piedmont hatchery (Italy) was selected based on farm clinical signs and the Astrovirus serological positivity in the breeder farm. The viral dynamics was followed from the hatchery to the farm. The presence of both CAstV and ANV was monitored by evaluating the viral load, in environmental and animal samples. Interestingly, both viruses were detected in chick yolk sacs at 18th day incubation, in the gut contents of 1-day chicks, whereas the hatchery environmental samples, the external eggs' surfaces and the embryos intestinal contents were negative. The CAstV copy number was higher in animal tissues from hatchery, while a greater ANV load was detected in animal tissue from farm. Moreover, our data suggested a vertical transmission ascribed to both viruses. A frequent co-infection was also observed in samples from both hatchery and farm. Lastly, the first Italian full-length genome and molecular characterization of ANV was obtained.

Birthmode and environment-dependent microbiota transmission dynamics are complemented by breastfeeding during the first year.

The composition and maturation of the early-life microbiota are modulated by a number of perinatal factors, whose interplay in relation to microbial vertical transmission remains inadequately elucidated. Using recent strain-tracking methodologies, we analyzed mother-to-infant microbiota transmission in two different birth environments: hospital-born (vaginal/cesarean) and home-born (vaginal) infants and their mothers. While delivery mode primarily explains initial compositional differences, place of birth impacts transmission timing-being early in homebirths and delayed in cesarean deliveries. Transmission patterns vary greatly across species and birth groups, yet certain species, like Bifidobacterium longum, are consistently vertically transmitted regardless of delivery setting. Strain-level analysis of B. longum highlights relevant and consistent subspecies replacement patterns mainly explained by breastfeeding practices, which drive changes in human milk oligosaccharide (HMO) degrading capabilities. Our findings highlight how delivery setting, breastfeeding duration, and other lifestyle preferences collectively shape vertical transmission, impacting infant gut colonization during early life.

Transmission of Oyster Mushroom Spherical Virus to Progeny via Basidiospores and Horizontally to a New Host Pleurotus floridanus.

Mycoviruses are usually transmitted horizontally via hyphal anastomosis and vertically through sporulation in natural settings. Oyster mushroom spherical virus (OMSV) is a mycovirus that infects Pleurotus ostreatus, with horizontal transmission via hyphal anastomosis. However, whether OMSV can be vertically transmitted is unclear. This study aimed to investigate the transmission characteristics of OMSV to progeny via basidiospores and horizontally to a new host. A total of 37 single-basidiospore offspring were obtained from OMSV-infected P. ostreatus and Pleurotus pulmonarius for Western blot detection of OMSV. The OMSV-carrying rate among monokaryotic isolates was 19% in P. ostreatus and 44% in P. pulmonarius. Then, OMSV-free and OMSV-infected monokaryotic isolates were selected for hybridization with harvested dikaryotic progeny strains. Western blot analyses of the offspring revealed that the OMSV transmission efficiency was 50% in P. ostreatus and 75% in P. pulmonarius, indicating vertical transmission via sexual basidiospores. Furthermore, we observed the horizontal transfer of OMSV from P. pulmonarius to Pleurotus floridanus. OMSV infection in P. floridanus resulted in significant inhibition of mycelial growth and yield loss. This study was novel in reporting the vertical transmission of OMSV through basidiospores, and its infection and pathogenicity in a new host P. floridanus.

Intracellular symbiont Symbiodolus is vertically transmitted and widespread across insect orders.

Insects engage in manifold interactions with bacteria that can shift along the parasitism-mutualism continuum. However, only a small number of bacterial taxa managed to successfully colonize a wide diversity of insects, by evolving mechanisms for host-cell entry, immune evasion, germline tropism, reproductive manipulation, and/or by providing benefits to the host that stabilize the symbiotic association. Here we report on the discovery of an Enterobacterales endosymbiont (Symbiodolus, type species S. clandestinus) that is widespread across at least six insect orders and occurs at high prevalence within host populations. Fluorescence in situ hybridization in several Coleopteran and one Dipteran species revealed Symbiodolus' intracellular presence in all host life stages and across tissues, with a high abundance in female ovaries, indicating transovarial vertical transmission. Symbiont genome sequencing across 16 host taxa revealed a high degree of functional conservation in the eroding and transposon-rich genomes. All sequenced Symbiodolus genomes encode for multiple secretion systems, alongside effectors and toxin-antitoxin systems, which likely facilitate host-cell entry and interactions with the host. However, Symbiodolus-infected insects show no obvious signs of disease, and biosynthetic pathways for several amino acids and cofactors encoded by the bacterial genomes suggest that the symbionts may also be able to provide benefits to the hosts. A lack of host-symbiont cospeciation provides evidence for occasional horizontal transmission, so Symbiodolus' success is likely based on a mixed transmission mode. Our findings uncover a hitherto undescribed and widespread insect endosymbiont that may present valuable opportunities to unravel the molecular underpinnings of symbiosis establishment and maintenance.

Dynamics, diversity, and roles of bacterial transmission modes during the first asexual life stages of the freshwater sponge Spongilla lacustris.

BACKGROUND: Sponge-associated bacteria play important roles in the physiology of their host, whose recruitment processes are crucial to maintain symbiotic associations. However, the acquisition of bacterial communities within freshwater sponges is still under explored. Spongilla lacustris is a model sponge widely distributed in European rivers and lakes, producing dormant cysts (named gemmules) for their asexual reproduction, before winter. Through an in vitro experiment, this study aims to describe the dynamics of bacterial communities and their transmission modes following the hatching of these gemmules. RESULTS: An overall change of bacterial ß-diversity was observed through the ontology of the juvenile sponges. These temporal differences were potentially linked, first to the osculum acquisition and the development of a canal system, and then, the increasing colonization of the Chlorella-like photosymbionts. Gemmules hatching with a sterilized surface were found to have a more dispersed and less diverse microbiome, revealing the importance of gemmule epibacteria for the whole holobiont stability. These epibacteria were suggested to be vertically transmitted from the maternal tissues to the gemmule surface. Vertical transmission through the incorporation of bacterial communities inside of the gemmule, was also found as a dominant transmission mode, especially with the nitrogen fixers Terasakiellaceae. Finally, we showed that almost no ASVs were shared between the free-living community and the juveniles, suggesting that horizontal recruitment is unlikely to happen during the first stages of development. However, the free-living bacteria filtered are probably used as a source of nutrients, allowing an enrichment of copiotrophic bacteria already present within its microbiome. CONCLUSIONS: This study brings new insight for a better understanding of the microbiome acquisition during the first stages of freshwater sponge development. We showed the importance of epibacterial communities on gemmules for the whole holobiont stability, and demonstrated the near absence of recruitment of free-living bacteria during the first stages.

Transmission dynamics of symbiotic protist communities in the termite gut: association with host adult eclosion and dispersal.

The fidelity of vertical transmission is a critical factor in maintaining mutualistic associations with microorganisms. The obligate mutualism between termites and intestinal protist communities has been maintained for over 130 million years, suggesting the faithful transmission of diverse protist species across host generations. Although a severe bottleneck can occur when alates disperse with gut protists, how protist communities are maintained during this process remains largely unknown. In this study, we examined the dynamics of intestinal protist communities during adult eclosion and alate dispersal in the termite Reticulitermes speratus. We found that the protist community structure in last-instar nymphs differed significantly from that in workers and persisted intact during adult eclosion, whereas all protists disappeared from the gut during moults between worker stages. The number of protists in nymphs and alates was substantially lower than in workers, whereas the proportion of protist species exhibiting low abundance in workers was higher in nymphs and alates. Using a simulation-based approach, we demonstrate that such changes in the protist community composition of nymphs and alates improve the transmission efficiency of whole protist species communities. This study thus provides novel insights into how termites have maintained mutualistic relationships with diverse gut microbiota for generations.