Comparison of praziquantel efficacy at 40 mg/kg and 60 mg/kg in treating Schistosoma haematobium infection among schoolchildren in the Ingwavuma area, KwaZulu-Natal, South Africa

Background. The World Health Organization recommends praziquantel (PZQ) (40 mg/kg body weight) for treating schistosomiasis. However, drug failure has been reported, prompting use of 60 mg/kg, for which results have been inconsistent.Objectives. To compare the efficacy of PZQ 40 mg/kg and 60 mg/kg in treating schoolchildren infected with Schistosoma haematobium.Methods. The study was conducted during November 2017 - August 2018 in the Ingwavuma area, uMkhanyakude District, KwaZulu-Natal Province, South Africa. Children aged 10 - 15 years were screened for S. haematobium using a filtration technique. Infected children were randomly assigned to a dose of PZQ of 40 mg/kg or 60 mg/kg. Side-effects were recorded within 24 hours after treatment using questionnaires and direct observation. Four weeks after treatment, participants were retested for S. haematobium infection. Baseline and post-treatment mean egg counts were calculated. Cure rate (CR) and egg reduction rate (ERR) were used to determine PZQ efficacy, while repeated-measures analysis of variance determined the effect of both doses on infection intensity. A χ2 test was used to determine the association of side-effects with treatment, with a p-value ≤0.05.Results. Forty-three and 36 children were treated with PZQ 40 mg/kg and 60 mg/kg, respectively. The 40 mg/kg group had a CR of 79.0% and an ERR of 97.2%, and the 60 mg/kg group a CR of 83.0% and an ERR of 98.3%. The effect of dose on infection intensity was not significantly different between the two groups (p>0.05). Abdominal pains, dizziness and fatigue were common among children who received PZQ 40 mg/kg, while headache, dizziness and nausea were common in the 60 mg/kg group.Conclusions. The efficacy of PZQ at 60 mg/kg was similar to that at 40 mg/kg. A dose >40 mg/kg therefore does not add value in treating S. haematobium infection. Transient side-effects (mostly dizziness) were observed more in the 60 mg/kg group than in the 40 mg/kg group. We recommend continued use of 40 mg/kg body weight for treating schistosomiasis.

Epidemiological studies of parasitic gastrointestinal nematodes, cestodes and coccidia infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

Between January 1999 and December 2000 faecal samples from 16 264 cattle at 12 dipping sites in the highveld and nine in the lowveld communal grazing areas of Zimbabwe were examined for gastrointestinal (GI) nematode and cestodes eggs, and coccidia oocysts. Strongyle larvae were identified following culture of pooled faecal samples collected at monthly intervals. The effects of region, age, sex and season on the prevalence of GI nematodes, cestodes and coccidia were determined. Faecal egg and oocyst counts showed an overall prevalence of GI nematodes of 43 %, coccidia 19.8 % and cestodes 4.8 %. A significantly higher prevalence of infection with GI nematodes, cestodes and coccidia was recorded in calves (P < 0.01) than in adults. Pregnant and lactating cows had significantly higher prevalences than bulls, oxen and non-lactating (dry cows) (P < 0.01). The general trend of eggs per gram (epg) of faeces and oocysts per gram (opg) of faeces was associated with the rainfall pattern in the two regions, with high epg and opg being recorded during the wet months. The most prevalent genera of GI nematodes were Cooperia, Haemonchus and Trichostrongylus in that order. Strongyloides papillosus was found exclusively in calves. Haemonchus was significantly more prevalent during the wet season than the dry season (P < 0.01). In contrast, Trichostrongylus was present in significantly (P < 0.01) higher numbers during the dry months than the wet months, while Cooperia and Oesophagostomum revealed no significant differences between the wet and dry season. These findings are discussed with reference to their relevance for strategic control of GI parasites in cattle in communal grazing areas of Zimbabwe

Experimental infections of baboons (Papio spp.) and vervet monkeys (Cercopithecus aethiops) with Trichinella zimbabwensis and successful treatment with ivermectin.

Experimental Trichinella zimbabwensis infections were established in three baboons (Papios p.)and four vervet monkeys (Cercopithecuase thiops) and the clinical-pathological manifestations assessed. The infected animals showed clinical signs ranging from fever, diarrhoea, periorbitaol edema and muscular pain in varying degrees. One baboon became blind due to the infection. Levels of creatinine phosphokinase and lactated ehydrogenase increased to reach a peak on Day 42 post-infection(pi)for both baboons and monkeys. Blood parameters such as packed cell volume, levels of red blood cells and white blood cells did not change significantly from the normal ranges except for the levels of eosinophils which peaked above the normal ranges at Day 28 and 56 pi in baboons and at Day 56 pi in monkeys

Observations on mass production of <i>Calicophoron microbothrium</i> metacercariae from experimentally and naturally infected <i>Bulinus tropicus</i>

In an attempt to establish an ideal method for mass production of Calicophoron microbothrium metacercariae, a study was carried out to compare the shedding capacities of Bulinus tropicus naturally and experimentally infected with C. microbothrium. A total of 906 F1 B. tropicus between 4 and 5 weeks old were each experimentally infected with two C. microbothrium miracidia and monitored for 12 weeks. The infected snails were fed on dried lettuce and fish flakes and were kept in 1 l plastic aquaria housed in a snail room where temperature, light and humidity were controlled. Seventy-four percent of the experimentally infected snails died during the prepatent period and of the remaining, only 13.2 % developed patent infection, while 12.5 % were refractory. Snail growth rate was poor and the average shedding rate was 20 cercariae per snail per day. Compared to the experimentally infected snails, 2 200 adult B. tropicus, collected from the field and naturally infected with C. microbothrium, yielded high numbers of metacercariae. Eighty-four percent of the snails died within 7 weeks of the study with peak mortality occurring from the 2nd to the 4th week of infection and coinciding with an overall decrease in the number of cercariae shed

The occurrence of Trichinella zimbabwensis in naturally infected wild crocodiles (Crocodylus niloticus) from the Kruger National Park, South Africa

Trichinella zimbabwensis has been found naturally infecting crocodiles (Crocodylus niloticus) in Zimbabwe, Mozambique, Ethiopia and South Africa, as well as monitor lizards (Varanus niloticus) in Zimbabwe. The reports on natural infections were mostly accidental rather than structured surveys and involved very few animals. Previous surveillance studies in South Africa reported a 38.5% prevalence of T. zimbabwensis among wild crocodiles tested from the Mpumalanga province and Kruger National Park (KNP). No studies have been conducted to date on the geographical distribution and occurrence of T. zimbabwensis in wild crocodiles and varans in countries in southern Africa. Recent outbreaks of pansteatitis in crocodile populations of the KNP, South Africa, provided an opportunity to conduct a more structured survey aimed at elucidating the occurrence and distribution of T. zimbabwensis in culled wild crocodile populations within the KNP. Results from this study showed that T. zimbabwensis occurred in 10 out of 12 culled crocodiles form the KNP. The results also showed that the natural distribution of T. zimbabwensis in crocodiles includes all the major river systems in the KNP. The predilection sites of larvae in muscles followed a different pattern in naturally infected crocodiles compared to observations in experimentally infected mammalian hosts.The authors wish to thank the rangers and scientific services staff of KNP responsible for the capture, euthanasia and transport of crocodiles. Our sincere thanks for the assistance received from the state veterinarian, Nelspruit, with the collection of samples; Dr Huchzermeyer for his assistance with necropsies; the invaluable insight into crocodilian anatomy and physiology provided by Drs Huchzermeyer, Webb, Manolis and Richardson; to Mrs T. La Grange, staff and students of the School for Biological and Conservation Sciences of the University of KwaZulu-Natal for their assistance in testing of samples; the International Trichinella Reference Centre for species confirmation; and Mr F. Koegelenberg for his assistance in the drafting of fig. 1.http://journals.cambridge.org/action/displayJournal?jid=JHLam2013mn201

Transmission studies on Trichinella species isolated from Crocodylus niloticus and efficacy of fenbendazole and levamisole against muscle L1 stages in Balb C mice

Forty four Balb C mice, aged 18 weeks were infected with crocodile ( Crocodylus niloticus)-derived Trichinella species. Of the infected mice, 32 were randomly divided into two groups each containing equal numbers of males and females; levamisole treated group and fenbendazole treated group. Each group was randomly subdivided into two subgroups as follows: levamisole group (subgroup 1: treated with levamisole on day 35 post infection and subgroup 2: treated with levamisole on days 35 and 42 post infection) and fenbendazole group (subgroup 1: treated with fenbendazole on day 35 post infection and subgroup 2: treated with fenbendazole on days 35 and 42 post infection). The first sub-groups treated on day 35 post infection were slaughtered on day 42 post infection and the second subgroups were treated on days 35 and 42 post infection and slaughtered on day 49 post infection. Two female mice were infected a day after mating and were slaughtered together with the offspring on day 64 post-infection. Ten infected control mice were given 1 ml distilled water orally as placebo, and five of these were slaughtered on day 42 post infection. The results showed that the mean reproductive capacity index of this strain (RCI) in Balb C mice was 110. There was a significant reduction ( P<0.01) in larval counts in the single treatment groups (day 35) and in the double treatment groups (days 35 and 42) for both anthelmintics when compared the number of parasites in the control groups. After a single treatment, levamisole reduced the infection by 79.9% and fenbendazole by 76.7%. Following double treatments, levamisole reduced the infection by 95.5% and fenbendazole by 99.1%. There was evidence that the infected pregnant mice transmitted the parasite to their offspring. It is not certain whether the parasite was transmitted congenitally or transmammary. Alternative ways of controlling the parasite in crocodile farms in Zimbabwe are discussed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Research Board of the University of Zimbabwe.mn201