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Background The Lake Victoria basin is one of the most persistent hotspots of schistosomiasis in Africa, the intestinal form of the disease being studied more often than the urogenital form. Most schistosomiasis studies have been directed to Schistosoma mansoni and their corresponding intermediate snail hosts of the genus Biomphalaria , while neglecting S. haematobium and their intermediate snail hosts of the genus Bulinus . In the present study, we used DNA sequences from part of the cytochrome c oxidase subunit 1 ( cox 1) gene and the internal transcribed spacer 2 (ITS2) region to investigate Bulinus populations obtained from a longitudinal survey in Lake Victoria and neighbouring systems during 2010–2019. Methods Sequences were obtained to (i) determine specimen identities, diversity and phylogenetic positions, (ii) reconstruct phylogeographical affinities, and (iii) determine the population structure to discuss the results and their implications for the transmission and epidemiology of urogenital schistosomiasis in Lake Victoria. Results Phylogenies, species delimitation methods (SDMs) and statistical parsimony networks revealed the presence of two main groups of Bulinus species occurring in Lake Victoria; B. truncatus / B. tropicus complex with three species ( B. truncatus , B. tropicus and Bulinus sp. 1), dominating the lake proper, and a B. africanus group, prevalent in banks and marshes. Although a total of 47 cox 1 haplotypes, were detected within and outside Lake Victoria, there was limited haplotype sharing (only Haplotype 6 was shared between populations from Lake Victoria open waters and neighbouring aquatic systems) – an indication that haplotypes are specific to habitats. Conclusions The Bulinus fauna of Lake Victoria consists of at least B. truncatus , B. tropicus , Bulinus sp. 1 ( B. trigonus ?) and B. ugandae . The occurrence and wide distribution of Bulinus species in Lake Victoria potentially implies the occurrence of urogenital schistosomiasis in communities living along the shores and on islands of the lake who depend solely on the lake for their livelihood. More in-depth studies are needed to obtain a better picture of the extent of the disease in the Lake Victoria basin.

Background Snails such as Galba truncatula are hosts for trematode flukes causing fascioliasis, a zoonosis that is a major public health problem. Galba truncatula has recently been shown to be a cryptic species complex. African populations of Galba spp. are not yet studied using molecular assessments and is imperative to do so and reconstruct the centre of origin of Galba and to understand when and by what means it may have colonized the highlands of Africa and to what extent humans might have been involved in that process. Methods Samples from all known sub-ranges throughout Africa and new samples from Europe and Asia were obtained. We used a combination of two mitochondrial ( cox 1 and 16S ) and one nuclear (ITS2) markers and phylogenetic, divergence time estimates and phylogeographical methods to determine the identity and biogeographical affinities. We also reconstructed the colonization history including the likely mode of dispersal and tested for the presence of cryptic Galba species in Africa. Results Galba truncatula is restricted to the Palaearctic region of the continent, namely Morocco. All sub-Saharan populations proved to be a distinct species according to the phylogenetic analyses and genetic distance. We propose to use the existing name Galba mweruensis (Connolly, 1929) for this species which is morphologically indistinguishable from the other two species hitherto known to occur in northern Africa, i.e. G. truncatula and G. schirazensis . Sub-tropical Africa has been colonized only once in either the Pliocene and possibly Miocene. Diversification within G. mweruensis is dated to the Plio-Pleistocene and thus human-mediated dispersal can be ruled out for the initial colonization of the isolated mountain ranges. There are potentially even more cryptic species in high altitude areas of Africa as outlined by the distinctness of the population found at the top of Mt. Elgon, Uganda. Conclusions From a novel genetic inspection of available African material, a hitherto neglected distinct species, G. mweruensis , now appears a major host of F. hepatica throughout sub-Saharan Africa. A closer examination of trematode parasites hosted by this species is needed in order to understand transmission patterns in highlands throughout eastern and southern Africa. We encourage future studies to inspect other high altitudes areas in Africa in light of parasites of either veterinary or medical importance.

The emergence of insecticide resistance among malaria vector populations poses a significant threat to existing malaria vector control tools. This phenomenon necessitates an increased pace of developing and deploying new effective compounds in insecticides for vector control. Therefore, this study investigated the comparative performance of newly formulated indoor residual spray compounds, Klypson 500WG (Clothianidin alone) and 2GARD-WP (a mixture of Clothianidin 50% and Deltamethrin 6.25%) against An. gambiae in the lower Moshi area of the rural Moshi district, Tanzania. Before the wall cone bioassay tests, the susceptibility of field-collected adult 'An. gambiae' s.l. to 0.75% Permethrin, 2% Klypson 500WG, 0.05% Deltamethrin, and 0.25% Pirimiphos-methyl was assessed following WHO procedures. For the cone-bioassay testing, 160 houses were randomly selected and sprayed with Klypson 500WG and 2GARD-WP. For the walls sprayed with Klypson 500WG and 2GARD-WP, the knockdown rate of 'Anopheles gambiae' after 60 min of exposure over six months ranged from 70% to 98%, with mortality rates after 24 to 168 h consistently exceeding 90% across all villages and wall types throughout the six months. The susceptibility of wild-collected mosquitoes to Pirimiphos-Methyl, Permethrin, Deltamethrin, and Klypson 500WG was 61, 81, 86, and 93%, respectively. These findings suggest that Klypson 500WG and 2GARD-WP are suitable alternative insecticides that can be incorporated in the vector control toolbox used for malaria control.

Invasive species cause major losses in biodiversity worldwide and alter ecosystem functioning. Once established, invaders are often impossible to remove from ecosystems, especially in eco-insular systems such as the African Great Lakes. How intrinsic biological properties of invasive taxa interact with human-induced ecosystem modifications is a crucial factor determining invasiveness and our ability to anticipate, prevent and manage bioinvasions. Here we investigate the influence of temperature on key life-history traits, including fecundity, growth, offspring size, survival and parental immune investments, of invasive Asian Melanoides tuberculata (Müller, 1774) from Lake Malawi/Nyassa (morph LMI). We subjected populations of this parthenogenetic (clonal) lineage to uniform temperature treatments of 20 °C, 26 °C and 32 °C and monitored adult and juvenile life-history traits. Constitutive (preventative) and infection-induced immune investments of adults were estimated via antibacterial responses to a natural pathogen. Fecundity was low during our experiment and did not differ amongst temperature treatments, but a burst of offspring release occurred in the first two weeks of the experiment. Juvenile size and growth increased with temperature, which resulted in decreasing generation times. Juvenile mortality was, however, elevated at 32 °C. Temperature differences prompted a shift in immune investments. Under cold temperatures, adults invested in costly constitutive immunity, but they did not in warm environments, where strong investments in infection-induced immune responses occurred. This strategy may enable adults in warm environments to redirect energy from immunity to growth and reproduction, therewith, enhancing competitiveness at the cost of reduced offspring survival. We observed contrasting responses in various studied traits, suggesting that Melanoides tuberculata adopts compensatory mechanisms to cope with environmental changes. This versatility favours invasiveness and contributes to the competitive pressure which invasive Melanoides exerts on native taxa amid global warming and ecosystem change. Understanding the intricate interactions between bioinvasions and environmental change is essential for effective conservation of native species, the stability of their ecosystems and for policy development. Species-specific versatility of invasive species and associated competitive advantages remain understudied, but are critical to predict invasion dynamics in the context of multidimensional anthropogenic stressors, for informed risk assessment and decision-making.

The human-mediated transfers of tilapia for aquaculture as a panacea for food insecurity in Africa have led to unprecedented and irreversible impacts on native ichthyofaunal biodiversity. Though aquaculture has been pointed to as the main gateway to species introductions in the Pangani system, formal documentation on how it has contributed to such colonization is anecdotal. The present study aimed to genetically identify, update the list of introduced tilapia taxa, and authenticate if aquaculture is the main gateway to their widespread. We genetically identified non-native tilapias from the Pangani Catchment and aquaculture facilities by genotyping partial Mitochondrial DNA Control region. Molecular analyses depicted the Pangani Catchment to be exclusively inhabited by six non-native tilapiine taxa, particularly Oreochromis niloticus , Oreochromis leucostictus , Coptodon rendalli , Oreochromis esculentus , Oreochromis spilurus , and Oreochromis urolepis hornorum . Oreochromis niloticus , O. leucostictus , and C. rendalli were also predominant in aquaculture and shared haplotypes with their counterparts from the Pangani Catchment. We identified commercial strains of O. niloticus that also shared haplotypes between the two systems. Such haplotype sharing proves aquaculture is the gateway to introducing non-native tilapias into the Pangani Catchment. Thus, fish farming in the region should adhere to regional and international legislation to prevent future spillage.

Aim Cryptic invasions are an understudied phenomenon among species invasions, especially in freshwater invertebrates. We study the gastropod family Physidae, including the global invaders Physella acuta and several enigmatic Stenophysa species, their phylogenetic relationships and the presence of native species among African Physidae. We infer distribution pattern, colonisation history and invasion ecology across Africa. Finally, we reconstruct the colonisation pathways and their timing into, across (and out of) Africa and model future dispersal. Location Global, with a focus on Africa and Indian Ocean islands. Methods Based on extensive sampling, multi‐gene phylogenetic, phylogeographic and ecological analyses, including species distribution modelling, we here examine Physidae globally. Results The Physidae probably originated in the Lower Cretaceous. A robust phylogeny showed four strongly supported genus‐level clades corresponding to Physella, Physa, Stenophysa and Aplexa. Physella acuta thrives in continental African countries and Indian Ocean islands. The African continent was colonised at least six times independently. For Stenophysa, the phylogeny suggests two independent transoceanic dispersal events into Africa and the Indian Ocean islands. Physella acuta occurs not only in artificial or highly disturbed habitats but also in large natural lakes. Stenophysa marmorata is ecologically flexible. The SDM for S. marmorata based on the selected climate variables predicted high probabilities of future occurrence in equatorial Africa and regions in the Indo‐Malayan Archipelago, New Guinea and eastern Australia. Main Conclusions Physidae contains examples of both intraspecific cryptic and interspecific cryptic invasions, with an intraspecific invasion of Physella acuta and a prime example of an interspecific cryptic invasion of Stenophysa spp. This study highlights the importance of cryptic invasions in freshwaters and also calls for their management. Stenophysa is likely to become pan‐tropical in the future. Physidae are an excellent model to study differential patterns and processes of intra‐ versus interspecific invasions at global and regional scales.