Infection and Vertical Transmission of Kamiti River Virus in Laboratory Bred Aedes aegypti Mosquitoes

Kamiti river virus (KRV) is an insect-only Flavivirus that was isolated from field-collected Ae. macintoshi mosquitoes in 1999, and is closely related to cell fusing agent virus. Both of these viruses belong to the family Flaviviridae, which also contains other viruses of medical importance, such as yellow fever virus, West Nile virus and dengue. Because Ae. macintoshi is the only known natural host to KRV, the main objective of this study was to establish the possibility that other mosquito hosts of the virus exist, by determining its ability to infect Ae. aegypti mosquitoes under laboratory conditions. The study also sought to determine the rates of infection and, subsequently, vertical transmission as a possible means of its maintenance and propagation in nature, given that it neither grows in vertebrate cells or mice. The mosquitoes were infected by the virus either as larvae or adults. Virus assay was done by re-isolation in tissue culture and indirect immunofluoresce assay methods. KRV infected Ae. aegypti mosquitoes, with the observed rates as high as 74 to 96 %. The virus was also transmitted vertically in these mosquitoes. Vertical transmission rates of 3.90 % were observed for the 2nd and 3rd ovarian cycles combined. These results suggest that Ae. aegypti mosquitoes are likely to be infected with KRV in nature, and that vertical transmission is the natural means by which it is maintained and propagated in this host, and possibly others

Cystic echinococcosis in donkeys in eastern Africa

Cystic echinococcosis (CE) is endemic in humans and domestic animals in eastern Africa. All the species of the Echinococcus granulosus sensu lato complex have been reported in this region except for E. equinus, possibly due to the small number of studies involving equids. This study reports the frequency of different Echinococcus species in donkeys from eastern Africa. A total of 5961 donkeys were examined during meat inspection in 3 slaughterhouses in Kenya. Identification of Echinococcus spp. was achieved through polymerase chain reaction-restriction fragment-length polymorphism and sequencing of the mitochondrial nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 1 gene. The prevalence of CE was 5.7% (337/5961). The 263 genotyped cysts belonged to E. equinus (n = 163), E. granulosus sensu stricto (n = 70), E. canadensis (G6/7) (n = 26) and E. ortleppi (n = 4). One donkey harboured a metacestode of Spirometra theileri. All E. equinus cases, except 2, originated from southern Ethiopia, whereas the other species were more evenly distributed across the study area. Most of the cysts belonging to E. equinus were fertile (111/163), while those of the other species were non-fertile. This is the first report of Echinococcus spp. in donkeys from sub-Saharan Africa and the first confirmation of E. equinus in East Africa. The frequent fertility of E. equinus cysts in donkeys affirms their suitability as intermediate hosts of this species, while low frequency and cyst fertility suggest a marginal role of donkeys in the transmission of E. granulosus s. s., E. canadensis (G6/7) and E. ortleppi

The potential role of roaming dogs in establishing a geographically novel life cycle of taeniids (Echinococcus spp. and Taenia spp.) in a non-endemic area

Cystic Echinococcosis (CE) is endemic in humans and livestock in many pastoral communities in Kenya. The distribution of the disease is enhanced by several factors, including livestock trade, which has allowed for the spread of CE to non-endemic areas such as western Kenya. Dogs' roaming behaviour, with consequent contamination of the environment with intestinal parasites, could then lead to parasite establishment. This study examined dogs' infection levels with taeniid eggs and their potential role in contaminating the environment with intestinal parasites. Methodology: We selected sixteen ruminant slaughterhouses in Busia and Bungoma Counties, and around each slaughterhouse we identified ten homesteads owning free-roaming dogs. We administered a questionnaire on dog management practices to the homestead owner and collected a faecal sample from the dog's rectum. In homesteads around 8 of the 16 slaughterhouses, we collared dogs with a GPS tracker to assess their movement patterns. The faecal samples were examined microscopically following zinc-chloride sieving-floatation technique for the presence of taeniid eggs and other canine intestinal parasites. Polymerase Chain Reaction – Restriction Fragment Length Polymorphism of NADH dehydrogenase subunit 1 gene and sequencing were used to confirm taeniid eggs identified during microscopy. Additionally, the Coproantigen-ELISA was used to detect the presence of taeniid antigen in a sub-set of the faecal samples. Results: Helminths detected in the 155 dogs sampled included hookworms (n = 92; 59.4%), ascarids (n = 15; 9.7%), and taeniids (n = 1; 0.6%). Through Copro-PCR, 13 eggs extracted from the sample of the only taeniid infected dog were sequenced and identified as E. canadensis (G6/7) [n = 1], Taenia multiceps [n = 1], and Taenia serialis [n = 6]; the remaining were indeterminate. Of the 77 faecal samples tested for E. granulosus sensu lato (s. l.) with the Copro-ELISA, 64 (83.1%) were negative, 12 (15.6%) were positive, while 1 (1.3%) was suspicious. The dogs travelled a median of 13.5 km daily, and 28 dogs visited the slaughterhouses during the 5-day recording period. Conclusion: The results indicate a relatively high carriage of zoonotic parasites by free-roaming domestic dogs in western Kenya, which poses a risk to human and livestock populations. We report for the first time a domestic lifecycle of Echinococcus canadensis and Taenia multiceps in western Kenya, as well as a presumptive sylvatic cycle of coenurosis by T. serialis. We recommend an extensive and ongoing Copro-antigen survey of dog faeces, broader assessment of dog parasites with zoonotic potential, adherence to slaughterhouse management practices, and dog-ownership programmes to highlight the importance of deworming and restricted dog movements

B-cell activity in children with malaria

Abstract Background Recent studies implicate deficiency of red blood cell (RBC) complement regulatory proteins (CR1 and CD55) in the pathogenesis of malarial anaemia. This study explored the involvement of B cell CD21, which has an analogous role to RBC CR1. Methods In a case control study conducted in Kisumu District hospital, western Kenya, children with severe malaria anaemia (SMA) and those with uncomplicated malaria (UM) were assessed by flow cytometry for B cells (CD20+) numbers, expression levels of CD21 and deposition of C3dg and by ELISA for soluble CD21 (sCD21). Paired t tests were used to determine statistical significance at a = 0.05. Results Children with SMA had significantly higher lymphocyte count (9,627.7 ± 8786.1 SD vs. 5,507 ± 2436 SD, P = 0.04 in the UM group) and the computed geometric mean of mature B-cell numbers based on the absolute lymphocyte count was significantly higher for SMA group: 1,823 (1,126 to 2,982, 95% CI) and 826.6 (564 to 1,220, 95% CI)] for UM group (P = 0.003). SMA group also had a higher percentage of CD20+ B cells (26.8 ± 9.7SD vs 20.9 ± 9.01 SD in the UM) (P = 0.03), indicating considerable polyclonal B-cell activation. The CD21 median flourescence intensity was lower in the SMA (246.4 ± 87.4 SD vs 369 ± 137.7 SD) (P 0.0001), probably due to complement mediated shaving of CD21 by fixed tissue macrophages. The CD20+ B cells of SMAs had higher levels of the complement split product C3dg (18.35 ± 10 SD vs 11.5 ± 6.8 S.D), (P = 0.0002), confirming possible role of complement in CD21 removal. Unexpectedly, the SMAs had lower levels of sCD21 (226.5 ± 131.5 SD vs 341.4 ± 137.3 SD in the UM) (P Conclusions These results implicate B-cell in pathophysiology of severe malaria that involves increased B-cell proliferation, increased complement deposition and subsequent loss of membrane-bound CD21. The loss of CD21 is not by the classical enzmatic cleavage.</p

Prevalence and Intensity of Gastrointestinal Parasites in Donkeys in Selected Abattoirs in Kenya

The aim of this study was to determine the prevalence and intensity of gastrointestinal parasites in donkeys slaughtered in Kinamba, Mogotio, and Lodwar slaughterhouses and their association with several host factors. A survey was done between July and September 2017 in three slaughterhouses. Faecal samples were collected per rectum from all the study donkeys for faecal egg counts (EPG) and morphological identification of the eggs. At slaughter, the gastrointestinal tracts were opened and examined visually, and all helminth parasites collected were subjected to morphological identification. Prevalence and intensity were calculated based on the helminth identified and EPG. A total of 282 donkeys were sampled. A majority of the donkeys (89%) were in poor body condition. Ten helminth parasite species were identified in 85.5% donkeys. They were Strongylus vulgaris (52.8%), Parascaris equorum (20.2%), Strongylus edentatus (12.1%), Anaplocephala perfoliata (10.3%), Setaria equina (3.5%) Anaplocephala magna (2.5%), Cylicocyclus auriculatus (2.1%), Cyathostomum species (1.8%), Strongylus equinus (0.4%), and Triodontophorus serratus (0.4%). A significant percentage (55.3%) had no eggs in their feces, 39% had low infection, 5% had medium, and only 0.7% were heavily infected. Prevalence rates via use of the EPG showed Strongyles (44.7%), Parascaris equorum (5.3%), Oxyuris equi (11%), Triodontophorus tenuicolis (0.7%), Habronema species (0.7%), and cestodes eggs (0.4%). No significant differences were observed between fecal Strongylus egg count and age, sex, and pregnancy status. However, donkeys with poor body condition shed more Strongylus eggs in feces. Helminth infections are prevalent in donkeys in Kenya; however, this is not reflected in coprological analyses. These helminth parasites may contribute to poor body condition, ill health, and poor productivity of donkeys

Findings of a community screening programme for human cystic echinococcosis in a non-endemic area

Cystic Echinococcosis (CE) is a zoonosis caused by infection with the larval stages of the taeniid cestodes of the species complex Echinococcus granulosus sensu lato. It is prevalent among transhumant communities in East Africa, including those residing in northern Kenya. The movement of livestock from these regions of high incidence to areas of low incidence creates an indirect risk of disease spill-over to humans. To assess possible establishment of the CE life cycle outside known endemic regions, we used a portable ultrasound scanner to screen for the presence of human CE in Bungoma County of western Kenya, an area which imports substantial numbers of cattle for slaughter from neighbouring pastoralist regions. Eight sentinel sites were purposively selected based on their proximity to slaughterhouses handling animals introduced from pastoralist regions, and necessary permissions to conduct the study were sought. Regression analyses were conducted to identify risk factors associated with the presence of abdominal and cystic lesions (CL). In total, 1002 participants were screened; of these, 654 (65.3%) were female and the median age was 43. Farming (n = 403; 43.4%) was the most frequent occupation, followed by professional (i.e. on regular salary) (n = 215; 23.1%), and business (n = 207; 22.3%) categories. Sixty-seven participants (6.7%) had abnormal ultrasound findings, of these, 7 (1.1%) had simple liver cysts/CL, as per WHO classification. As such, their outcome was inconclusive and they were not put on treatment but advised to attend follow-up investigations in a referral health facility. Other abnormal findings included splenomegaly (n = 14), ovarian cysts (n = 14), uterine fibroids (n = 10), polycystic kidneys (n = 6), and benign prostatic hyperplasia (n = 6). Age was unconditionally associated with the presence of presumptive CL. These results contribute to CE baseline data while providing insights on the implementation of ultrasound diagnosis in the field, as recommended by the WHO for targeted control of echinococcosis by 2030.</jats:p

Prevalence and Diversity of Cystic Echinococcosis in Livestock in Maasailand, Kenya

Journal ArticleCystic echinococcosis (CE) is a zoonotic disease caused by several members of the Echinococcus granulosus species complex. In East Africa, several species/strains are known to occur in livestock and humans, but host preferences, relative frequencies and spatial distribution of these taxa are poorly known. Here, we contribute livestock data for Maasailand of southern Kenya. Total CE prevalence was 25.8 % in cattle (151/587), 16.5%in sheep (71/430) and 10.8%in goats (21/194), which is a significant increase compared to surveys done about three decades ago. The majority of cysts occurred in the liver (56 % in cattle, 70 % in sheep and 65 % in goats). Molecular characterization by PCR–RFLP and sequencing of parts of the mitochondrial nad-1 gene was done for a subsample of 285 cysts. E. granulosus G1 was dominant in all host species (200 of 201 cysts from cattle, 68 of 69 from sheep and 11 of 15 from goats); the remaining taxa were Echinococcus canadensis G6 (one cyst from sheep, four from goats) and Echinococcus ortleppi (one cyst from cattle). Considering cyst fertility, sheep appear to be the most important hosts for E. granulosusG1, while goats were found to be suitable hosts for E. canadensis G6 (three of four cysts were fertile). For the first time, E. ortleppi was found in cattle from southern Kenya. Our data show an intense and possibly increasing level of CE transmission in southern Kenya, and the predominance of E. granulosus G1, which appears to be particularly pathogenic to humans, calls for urgent control measures