Pulmonary hypertension in adults completing tuberculosis treatment.

Background: Pulmonary hypertension (PH) after tuberculosis (TB) is typically not included among the chronic lung diseases causing PH (group 3 PH), with few data available to support the inclusion. Objectives: To determine the prevalence of PH in an adult population completing TB treatment. Methods: This single-centre, cross-sectional study only included patients with their first documented episode of TB, and who were in the second half of treatment or had recently completed treatment. PH was assessed using transthoracic echocardiography. Questionnaires were completed, and spirometry and a 6-minute walk test were performed. Results: One hundred patients were enrolled, with a mean age of 37.1 years, of whom 58% were male and 46% HIV positive. The median time since initiation of TB treatment was 22 weeks. The mean (standard deviation) measured right ventricular systolic pressure (RVSP) was 23.6 (6.24) mmHg. One participant had PH (defined as RVSP ≥40 mmHg; 95% confidence interval (CI) 0.0 - 3.0) and a further 3 had possible PH (RVSP ≥35 and <40 mmHg), with a combined PH prevalence of 4% (95% CI 0.2 - 7.8). Airflow obstruction on spirometry was found in 13.3% of 98 patients, while 25.5% had a reduced forced vital capacity. There was no association between RVSP or PH/possible PH and sex, age, HIV status, systemic hypertension, spirometry measurements or 6-minute walking distance. Smoking status was associated with RVSP, but not with the presence of PH/possible PH. Conclusion: There was a significant prevalence of PH in this preliminary study of predominantly young patients completing treatment for a first episode of TB. Larger and more detailed studies are warranted. Study synopsis: What the study adds. Of 100 adult patients with their first episode of tuberculosis (TB) who underwent echocardiograms near the end of treatment completion to determine the prevalence of pulmonary hypertension (PH), 1 (1%) had PH and a further 3 (3%) had possible PH. There was no association between sex, age, HIV status, lung function or 6-minute walking distance and the presence of PH. The study adds to the growing awareness of the association of TB with pulmonary vascular disease. It shows that even in a young population with a first episode of TB treated in an ambulatory setting, there is a significant prevalence of PH on treatment completion.Implications of the findings. Given that 10.6 million people acquire TB annually, the absolute global burden of cases with PH is likely to be high, but is underappreciated to date. Further work is urgently needed in this field.

Diversity and distribution of ectoparasite taxa associated with Micaelamys namaquensis (Rodentia: Muridae), an opportunistic commensal rodent species in South Africa.

South Africa boasts a rich diversity of small mammals of which several are commensal and harbour parasites of zoonotic importance. However, limited information is available on the parasite diversity and distribution associated with rodents in South Africa. This is particularly relevant for Micaelamys namaquensis (Namaqua rock mouse), a regionally widespread and locally abundant species that is often commensal. To address the paucity of data, the aims of the study were to record the ectoparasite diversity associated with M. namaquensis and develop distribution maps of lice and mites associated with M. namaquensis and other rodents in South Africa. Micaelamys namaquensis individuals (n = 216) were obtained from 12 localities representing multiple biomes during 2017­2018. A total of 5591 ectoparasites representing 5 taxonomic groups ­ fleas, lice, mesostigmatid mites, chiggers and ticks was recorded. These consisted of at least 57 taxa of which ticks were the most speciose (20 taxa). Novel contributions include new host and locality data for several ectoparasite taxa and undescribed chigger species. Known vector species were recorded which included fleas (Ctenocephalides felis, Dinopsyllus ellobius and Xenopsylla brasiliensis) and ticks (Haemaphysalis elliptica, Rhipicephalus appendiculatus and Rhipicephalus simus). Locality records indicate within-taxon geographic differences between the 2 louse species and the 2 most abundant mite species. It is clear that M. namaquensis hosts a rich diversity of ectoparasite taxa and, as such, is an important rodent species to monitor in habitats where it occurs in close proximity to humans and domestic animals.

Nematodes and cestodes of rodents in South Africa: baseline data on diversity and geographic distribution.

Currently, descriptive information on the host range and geographic distribution of helminth parasites associated with naturally occurring rodents in South and southern Africa is scant. Therefore, we embarked on a countrywide study to: (1) identify gastrointestinal helminths and their host range, and (2) provide baseline data on the geographic distribution of helminths across the country. Altogether, 55 helminth taxa were recovered from at least 13 rodent species (n = 1030) at 26 localities across South Africa. The helminth taxa represented 25 genera (15 nematodes, nine cestodes and one acanthocephalan). Monoxenous nematodes were the most abundant and prevalent group, while the occurrence of heteroxenous nematodes and cestodes was generally lower. The study recorded several novel helminth-host associations. Single-host-species infections were common, although multiple-host-species infections by helminth species were also recorded. Monoxenous nematodes and some cestodes were recovered countrywide, whereas heteroxenous nematodes were restricted to the eastern regions of South Africa. The study highlights the as yet unexplored diversity of helminth species associated with naturally occurring rodent species and provides initial data on their geographical distribution in South Africa.

Comparative mtDNA phylogeographic patterns reveal marked differences in population genetic structure between generalist and specialist ectoparasites of the African penguin (Spheniscus demersus).

To address factors affecting genetic diversity and dispersal of ectoparasites, we compared mitochondrial DNA (mtDNA) population genetic structures of the generalist soft tick Ornithodoros capensis to the more host-specific nest flea Parapsyllus humboldti. A total of 103 ticks and 92 fleas were sampled at five distinct South African island/mainland African penguin (Spheniscus demersus) colonies. With its wide host range, O. capensis showed no evidence of significant cytochrome c oxidase subunit I (COI) mtDNA population differentiation among the five sampling sites (φst = 0.00 ± 0.004; p = 0.80), as well as a higher level of genetic diversity (π = 0.8% ± 0.06%) when compared to P. humboldti. In contrast, the flea showed significant population structure among most of the same sampling sites (φst = 0.22 ± 0.11; p ≤ 0.05) and a lower level of genetic diversity (π = 0.2% ± 0.01%). Our findings suggest that despite both parasites being mostly nest bound, O. capensis have few barriers to dispersal among island and mainland colonies. However, P. humboldti are more dependent on the African penguin for dispersal and thus have more impediments to gene flow among the same colonies. These findings broadly support the SGVH (specialist generalist variation hypothesis) and provide the first evidence for this hypothesis in parasites restricted to seabird colonies.

Barriers and solutions to finding rifampicin-resistant tuberculosis cases in older children and adolescents.

Little is known about the barriers to post-exposure management of rifampicin-resistant tuberculosis (RR-TB) in older children and adolescents. We report on implementation lessons from a pilot programme targeting household-exposed individuals aged 6-18 years in Khayelitsha, South Africa. Barriers included misperceptions regarding risk of exposure, multiple research and implementation stakeholders, additional workload for an overburdened healthcare system, logistical issues faced by families, and insufficient human and financial resources. Solutions to these barriers are possible, but creativity and persistence are required. Our experience can guide others looking to roll-out care for children and adolescents exposed to RR-TB.

On connaît mal les entraves à la prise en charge post-exposition de la tuberculose résistante à la rifampicine (RR-TB) chez les enfants plus âgés et les adolescents. Nous rapportons les leçons de la mise en œuvre d'un programme pilote ciblant les individus exposés dans leurs foyers, âgés de 6­18 ans, à Khayelitsha, Afrique du Sud. Les obstacles ont inclus des perceptions erronées à propos du risque d'exposition, la multiplicité des partenaires de recherche et de mise en œuvre, la charge de travail supplémentaire pour un système de santé déjà surchargé, les problèmes logistiques auxquels sont confrontées les familles, et l'insuffisance des ressources humaines et financières. Il y a des solutions possibles à ces obstacles mais elles demandent de la créativité et de la détermination. Notre expérience peut guider ceux qui veulent lancer la prise en charge des enfants et des adolescents exposés à la RR-TB.

Se conoce poco sobre los factores que obstaculizan la atención después de la exposición a un caso de tuberculosis resistente a rifampicina (RR-TB) en los niños mayores y los adolescentes. En el presente artículo se describen las enseñanzas aprendidas durante la ejecución de un programa piloto dirigido a los contactos domiciliarios expuestos entre los 6 y los 18 años de edad, en Khayelitsha, Suráfrica. Entre los obstáculos observados se pueden citar las percepciones equivocadas sobre el riesgo de exposición, la multiplicidad de interesados directos en la investigación y la ejecución, la carga de trabajo adicional en un sistema de salud sobresaturado, los problemas organizativos afrontados por las familias y la insuficiencia de recursos humanos y de financiamiento. Las soluciones a estos problemas son posibles, pero exigen creatividad y persistencia. Esta experiencia puede orientar a otros equipos que intenten poner en marcha la atención de los niños y los adolescentes expuestos a la RR-TB.

Host range and distribution of small mammal fleas in South Africa, with a focus on species of medical and veterinary importance.

The host range and distribution of flea species on rodents and insectivores across multiple vegetation types in South Africa were investigated. Habitat suitability for flea species considered as important vectors of disease in humans and domestic animals was modelled. Data originated from fleas that were recovered from small mammals captured at 29 localities during 2009-2013 and published literature searched for flea records. Climate-based predictor variables, widely used in arthropod vector distribution, were selected and habitat suitability modelled for 10 flea vector species. A total of 2469 flea individuals representing 33 species and subspecies were collected from 1185 small mammals. Ten of each of the flea and rodent species are plague vectors and reservoirs, respectively. Multiple novel flea-host associations and locality records were noted. Three vector species were recorded from insectivores. Geographic distributions of flea species ranged from broad, across-biome distributions to narrower distributions within one or two biomes. Habitat suitability models performed excellently for the majority of flea vectors and identified regions of summer and all-year rainfall as representing suitable habitats for most vector species. Current knowledge of vector and disease ecology can benefit from similar sampling approaches that will be important not only for South Africa, but also for the sub-region.

Ixodid ticks on domestic dogs in the Northern Cape Province of South Africa and in Namibia.

The objective of this study was to determine the species composition of ixodid ticks infesting domestic dogs in the northwestern region of the Northern Cape Province of South Africa and in Namibia. Ticks were collected from February 2008 to January 2009 from dogs presented for a variety of reasons at a veterinary clinic in the Northern Cape Province and at 3 clinics in Namibia. The ticks collected at each place were pooled separately for each month at each locality. Eleven ixodid tick species were collected from dogs in the Northern Cape Province and new locality records for Haemaphysalis colesbergensis and Ixodes rubicundus, new locality and host records for Hyalomma glabrum, and a new host record for Rhipicephalus neumanni are reported. Six tick species were collected from dogs at the 3 clinics in Namibia. The most numerous species on dogs in both countries was R. sanguineus. The present results increase the total number of ixodid tick species collected from dogs in South Africa from 25 to 28.

Helminths in horses: use of selective treatment for the control of strongyles.

The current level of anthelmintic resistance in the horse-breeding industry is extremely high and therefore more emphasis is being placed on studies that focus on the judicious use of anthelmintic products. The aims of the study were to: 1) establish if there is variation in the egg excretion pattern of strongyles between the different age classes of Thoroughbred horses in the Western Cape Province (WCP), 2) test if a selective treatment approach successfully reduces the number of anthelmintic treatments and maintains acceptably low helminth burdens in adult Thoroughbred horses, and 3) evaluate the efficacy of subsampling large horse herds for faecal egg counts (FECs) to monitor the strongyle burden. In 2001 the FECs of 4 adult mare, 5 yearling and 3 weanling herds from 8 different farms were compared in the WCP Within the mare herds there were generally fewer egg-excreting individuals with lower mean FECs compared with the younger age classes. Individual faecal samples were collected every 3-4 weeks from 52 adult Thoroughbred mares from 1 farm in the WCP during a 12-month period (2002/2003). Animals with strongyle FECs > or =100 eggs per gram (epg ) were treated with an ivermectin-praziquantel combination drug (Equimax oral paste, Virbac). The mean monthly strongyle FEC for the entire group was <300 epg throughout the study and the number of treatments was reduced by 50 %. Resampling methods showed that an asymptote to mean FEC was reached at 55 animals for each of the pooled weanling, yearling and mare egg counts. Resampling within 4 different mare herds recorded asymptotes of between 24 and 28 animals. Subsampling entire herds for FECs therefore provided an effective approach to treatment management. This study demonstrates that selective treatment is both a practical and an effective approach to the management of anthelmintic resistance.

Anthelmintic treatment in horses: the extra-label use of products and the danger of under-dosing.

Anthelmintic products form the basis of helminth control practices on horse stud farms at present. Regular evaluation of the efficacy of these products is advisable, as it will provide information on the worm egg reappearance period and the resistance status in the worm population. The aim of this study was to evaluate the efficacy of doramectin, pyrantel pamoate, ivermectin and moxidectin on a Thoroughbred stud farm in the Western Cape Province, South Africa. The study also compared the anthelmintic efficacy of two moxidectin formulations administered at their recommended dosages (an injectable, at 0.2 mg/kg, not registered for horses, and an oral gel at 0.4 mg/kg, registered for horses). Two mixed-sex groups of 30 yearlings and 40 weaners were tested in 2001 and 2002, respectively, divided into 3 and 4 groups of equal size. In 2001, moxidectin was one of 3 drugs administered orally and at a dose rate of 0.4 mg/kg. In 2002, pyrantel pamoate and ivermectin were orally administered at 19 and 0.2 mg/kg. Moxidectin and doramectin (the latter not registered for horses) were administered by intramuscular injection at a dose of 0.2 mg/kg, the dosage registered for other host species. The faecal egg count reduction test was used to determine the anthelmintic efficacies in both years. Each animal acted as its own control and the arithmetic mean faecal egg count and lower 95% confidence limit was calculated for each of the groups. A 100% reduction in the faecal egg counts and a 100% lower 95% confidence limit was recorded for moxidectin (0.4 mg/kg) in 2001. In 2002, a 99% and 96% reduction was recorded for pyrantel pamoate and ivermectin, respectively. In the same year doramectin and moxidectin (both injectable and given at 0.2 mg/kg) did not have any effect on worm egg counts. Of the 4 drugs tested in 2002, only pyrantel pamoate recorded lower 95% confidence limits above 90%.

Impact of management interventions on helminth levels, and body and blood measurements in working donkeys in South Africa.

The aim of the study was to determine the effect of alternative management interventions on levels of nematodes and the condition of working donkeys in South Africa. Twenty-four adult donkeys (Equus asinus) within an area of 200km radius were randomly allocated to eight paddocks. Two replicates each of three management interventions together with a control group were tested in a 16-month study. The interventions included monthly removal of feces from paddocks where the donkeys grazed, a pre-winter moxidectin treatment, and a combination of a pre-winter moxidectin treatment and monthly fecal removal. The influence of the different interventions on the nematode fecal egg counts, animal live weights, body condition scores and general blood chemistry were compared. In addition, herbage samples were collected from the pastures in each paddock to determine the number of third-stage larvae (L(3)) per kg dry matter. At the end of the study worm recoveries and counts were performed on eight of the animals following euthanasia. The cyathostomes represented the largest portion of the helminth species composition in both the fecal egg counts and larval cultures. Monthly fecal removal alone did not significantly reduce the L(3) on pasture and consideration of more frequent removal is discussed. Pre-winter moxidectin treatment resulted in a 100% reduction in fecal egg counts, an average egg reappearance period of 42-55 days, a reduced average egg count for up to 8 months, and reduced total helminth burdens in all the treated donkeys. It also resulted in improved live weights, hemoglobin concentration, packed cell volumes and to some extent body condition score of the donkeys.

An introductory survey of helminth control practices in south africa and anthelmintic resistance on Thoroughbred stud farms in the Western Cape Province.

Fifty-one per cent of 110 questionnaires, designed for obtaining information on helminth control practices and management on Thoroughbred stud farms in South Africa, were completed by farmers during 2000. The number of horses per farm included in the questionnaire survey ranged from 15 to 410. Foals, yearlings and adult horses were treated with anthelmintics at a mean of 7.3 +/- 3.0, 6.6 +/- 2.7 and 5.3 +/- 2.3 times per year, respectively. An average of 3.4 different drugs were used annually, with ivermectin being used bymost farmers during 1997-2000. On 43% of farms the weights of horses were estimated by weigh band and 45% of farmers estimated visually, while both were used on 7% of farms and scales on the remaining 5%. Doses were based on average group weight on 50% ofthe farms and on individual weights on 46%. Forty-three per cent of farmers performed faecal egg count reduction tests (FECRT). Most farmers rotated horses between pastures and treated new horses at introduction. Faecal removal was practiced on 61% of farms and less than 50% of farmers used alternate grazing with ruminants. Faecal egg count reduction tests were done on 283 horses, using oxibendazole, ivermectin and moxidectin on 10,9 and 5 farms, respectively, in the Western Cape Province during 2001. While the efficacy of oxibendazole was estimated by FECRT to range from 0-88% and moxidectin from 99-100%, ivermectin resulted in a 100% reduction in egg counts. Only cyathostome larvae were recovered from post-treatment faecal cultures.

Prevalence and biodiversity of helminth parasites in donkeys from South Africa.

Seven donkeys (Equus asinus) from North-West and Mpumalanga Provinces in South Africa were examined at necropsy. Quantitative samples were collected from the gastrointestinal tract for recovery of helminth parasites from the stomach, small intestine, cecum, ventral colon, dorsal colon, descending colon, and cranial mesenteric artery. Fifteen genera and 29 species of helminths were identified comprising 27 species of nematodes in the Ascarididae, Atractidae, Habronematidae, Onchocercidae, Oxyuridae, and Strongylidae; 1 species of cestode in the Anoplocephalidae; and 1 species of trematode in the Paramphistomatidae. In addition, 2 species of oestrid fly larvae in the Gastrophiliidae were identified. The most abundant group in number of species was the cyathostomes (small strongyles) and, of these, Cyathostomum montgomeryi, Cylicocyclus sp. (a), and Cylicostephanus minutus were the most numerous. The most prevalent cyathostomes were C. montgomeryi and Cylicocyclus sp. n. (a). Strongylus vulgaris was the most abundant and prevalent large strongyle species. The occurrence of small strongyle species and their prevalences in this study are compared with 3 other studies on donkeys in Africa.

Sites of attachment and density assessment of ixodid ticks (Acari:Ixodidae) on impala (Aepyceros melampus).

During 1994 and 1995, 45 impala ewes, Aepyceros melampus were examined at Letaba Ranch in the Northern Province. Tick counts were made from 15 animals on three occasions, in July, October and February. The objective was to determine whether the total body tick counts can be estimated from counts done on specific, selected sampling sites on the skin. Twelve sites were shaved within ten predilection sites and the parasite numbers counted from these samples. These counts were compared to the total body parasite count as determined by the scrub and digestion techniques. More than 80% of all the ticks were present on the muzzle, the head, the pinna and the legs. Larger numbers of ticks were collected in October than in July or February. Two mathematical models were tested for the tick counts. The first model was made up of tick counts from a single shaved sampling site, the pinna. The correlation between the tick counts on the pinna and the total tick counts was highly significant (p values ranging between 0.0208 and 0.0001). The second model was developed based on tick counts from four regions, namely the head, the pinna and the front and hind feet. A less significant correlation was obtained between the number of ticks counted on the four sites and the total tick count.