A parasitological study carried out in May 2022 and March 2023 in the Nyando River of Lake Victoria Basin, Kenya, disclosed two parasitic lernaeid copepods: Lamproglena cleopatra Humes, 1957, from the gills of a cyprinid, the Ningu Labeo victorianus Boulenger, 1901, endemic to the Lake Victoria drainage system, and Lamproglena clariae Fryer, 1957, from a clariid, the North African catfish Clarias gariepinus (Burchell, 1822). The copepods were studied and supplementary taxonomic information was presented using scanning electron micrographs and genetic data. Scanning electron microscopy (SEM) provided information on the morphology of L. cleopatra’s antennae, oral region, thoracic legs (2–5), and furcal rami not previously reported. Analyses of the partial fragments of 18S and 28S rDNA and cytochrome c oxidase subunit 1 (cox1) of the two parasites showed them to be distinct from all other Lamproglena taxa retrieved from GenBank. This study presents new taxonomic information on morphology using SEM and provides the first ribosomal (18S and 28S rDNA) and mitochondrial (mtDNA) data for these two parasite species. The cox1 data provided are the first for all 38 nominal species of Lamproglena. Notably, the study also provides a new host record for L. cleopatra and extends the geographical information of this species to Kenya.

The discoveries of new taxonomic features of digenean species through the application of contemporary techniques, such as scanning electron microscopy (SEM) and molecular analysis are still growing. Two species of trematodes Glossidium pedatum and Tylodelphys mashonensis from the intestine and vitreous humour of Clarias gariepinus were recovered from Lake Ol’Bolossat, Kenya. The two endo-helminths were prepared for morphological examination using SEM and molecular characterisation. Additional morphological features were observed for G. pedatum such as domed papillae in the anterior extremity and a protruding cirrus which was unarmed, laterally folded and with a blunt tip as the first such observation for the genus and led to additional characteristics of the diagnosis of the genus. Tylodelphys mashonensis was characterised by a round oral sucker and tribocytic organ rounded with rows of papillae symmetrically arranged. The molecular analyses using ribosomal marker 28S large subunit (LSU) rDNA and mitochondrial (mtDNA) cytochrome c oxidase subunit 1 (cox1) for both G. pedatum and T. mashonensis confirmed the identity of the species and their phylogenetic relationship within the subclass Digenea. This study provides the first mitochondrial (mt)DNA sequence for G. pedatum and also extends the geographical record of two parasites to Kenya.

Lamproglena monodi Capart, 1944 adult females were first described from the Democratic Republic of the Congo and have been redescribed seven times from different cichlid species in Egypt, Burkina Faso and Brazil, all showing morphological variation. The adult male was first described from Lake Victoria and the Victoria Nile in Uganda. Copepods from the present study were collected from the gills of Oreochromis niloticus (Linnaeus, 1758) from Kibos Fish Farm, Kenya (between December 2017 and April 2018) and Sharqia Governorate (June 2019) and El-Minia (between July and December 2018) in Egypt. They were identified as L. monodi based on morphology and genetic data. Parasites were studied morphologically with the aid of light microscopy and scanning electron microscopy (SEM), and female infection levels calculated. Genetically, the specimens were studied using fragments of 18S and 28S rDNA. SEM analyses revealed additional diagnostic morphological features for the three adult males (elusive) and 249 females. These data were used to update the identification key for male Lamproglena species. Prevalence, mean intensity and mean abundance of the females were calculated as 13.5%, 8.6 and 1.2 respectively. Both 18S and 28S rDNA fragments confirmed the distinctness of L. monodi from previously characterised Lamproglena species, with distances of 1.22–1.94% (17–27 bp) for 18S rDNA and 15.66–18.1% (111–128 bp) for 28S rDNA. Haplotypes obtained from male and female specimens were identical, confirming the identity of the male specimens. This is the first genetic study of Lamproglena from Africa, the first SEM and genetic study of male L. monodi, and the first geographical report of this parasite from Kenya. The male and molecular data reported herein provide a useful point of reference for future Lamproglena studies.

During a parasitological survey carried out between May and August 2022 in the River Nyando, Lake Victoria Basin, a single species of Rhabdochona Railliet, 1916 (Nematoda: Rhabdochonidae) was recorded from the intestine of the Rippon barbel, Labeobarbus altianalis (Boulenger, 1900) (Cyprinidae). Based on light microscopy (LM), scanning electron microscopy (SEM) and DNA analyses the parasite was identified as Rhabdochona (Rhabdochona) gendrei Campana-Rouget, 1961. Light microscopy, SEM and DNA studies on this rhabdochonid resulted in a detailed redescription of the adult male and female. The following additional taxonomic features are described in the male: 14 anterior prostomal teeth; 12 pairs of preanal papillae: 11 subventral and one lateral; six pairs of postanal papillae: five subventral and one lateral, with the latter pair at the level of first subventral pairs when counted from the cloacal aperture. For the female: 14 anterior prostomal teeth and the size and absence of superficial structures on fully mature (larvated) eggs dissected out of the nematode body. Specimens of R. gendrei were genetically distinct in the 28S rRNA and cytochrome c oxidase subunit 1 (cox1) mitochondrial gene regions from known species of Rhabdochona. This is the first study that provides genetic data for a species of Rhabdochona from Africa, the first SEM of R. gendrei, and the first report of this parasite from Kenya. The molecular and SEM data reported herein provide a useful point of reference for future studies on Rhadochona in Africa.

Monopisthocotyleans of the genus Cichlidogyrus are ectoparasites which infest on skin, fins and gills of most teleosts in both capture fisheries and aquaculture. These parasites are often unnoticed, yet they cause damages to the organs they affect thereby increasing susceptibility of the fish to secondary infections. A total of fifty specimens of the introduced Redbelly tilapia Coptodon zillii (Gervais, 1848) were collected between November 2014 and April 2015 from Lake Naivasha, Kenya, and studied with the aim of collecting and identifying the gill monopisthocotyleans. Standard methods of parasitological examination were used in the identification of gill monopisthocotyla species. The collected monogeneans were preserved in 4% formalin for morphometric analysis. Seven Cichlidogyrus species were identified from the gills based on morphometric features of the opisthaptor and copulatory organs using identification keys. These include: Cichlidogyrus sclerosus Paperna & Thurston, 1969; C. tilapiae Paperna, 1960; C. digitatus Dossou, 1982; C. aegypticus Ergens, 1981; C. vexus Pariselle & Euzet, 1995; C. arthracanthus Paperna, 1960, and C. yanni Pariselle & Euzet, 1996. The C. digitatus was the most dominant with a prevalence of 42% among the other monopisthocotyleans on C. zillii in the lake. These monopisthocotyleans form the first biogeographical record of their occurrence on C. zillii in Lake Naivasha, Kenya.