Studies on Onchocerca gutturosa (Neumann, 1910) and its Development in Simulium ornatum (Meigen, 1818). I. Observations on O.gutturosa in cattle in South-East England

Eichler, D. A.; Nelson, G. S.

doi:10.1017/s0022149x00007136

Cited by 42 publications

(43 citation statements)

References 11 publications

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“…The data presented in Table III show consistently lower mean temperatures at Pentrefoelas than at Cynwyd throughout the transmission season. It is possible that the temperature at Pentrefoelas was too low to allow transmission of O. gutturosa, which would explain its absence from the upland sites throughout North Wales, and also its greater prevalence in the wanner South of England (extrapolated from EICHLER & NELSON, 1971).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies on the transmission of Onchocerca spp. in Britain (STEWARD, 1937;EICHLER, 1973a, b, c;EICHLER & NELSON, 1971) were made prior to the recognition of the identities of both species. This situation, therefore, presented an opportunity to investigate, for the first time, the transmission of O. lienalis in an area where it was the sole bovine Onchocerca species and, by comparing two areas where O. gutturosa did or did not occur, to try to identify its vector.…”

Section: Introductionmentioning

confidence: 99%

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Onchocerciasis in British cattle: a study of the transmission ofOnchocercasp. in North Wales

McCall

Trees

1993

J. Helminthol.

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The transmission of bovineOnchocercaspp. in Britain was investigated by studying the Ceratopogonidae and Simuliidae which attacked bait cattle between April and October at two sites in North Wales, where eitherOnchocerca lienalisandO. gutturosa(Cynwyd), orO. lienalisalone (Pentrefoelas) occurred. Based on the relative abundance of each species, their seasonal variation in abundance and preferential feeding sites on cattle, the presence ofOnchocercasp. infective larvae and the development of patent infections in bait cattle, vectors were identified asSimulium ornatums.1. at Pentrefoelas andS. reptansat Cynwyd (0·5% and 1·5% of parous flies infective, respectively). There was no significant difference between the lengths of the infective larvae from vectors at either site (Pentrefoelas: mean = 543·5 μm, SD = 29·45; Cynwyd: mean = 550·86 μm, SD = 35·26; p > 0·1), which were consistent with descriptions ofO. lienalis. The identity of a vector forO. gutturosawas not determined and the role of certain candidates is discussed. In this respect, the absence ofCulicoides nubeculosuswas notable. Transmission ofOnchocercasp. was limited to a short period of about 8 weeks, by a combination of vector abundance and parasite uptake from dermal skin layers, and a mean daily temperature requirement of 15°C or more for complete parasite development in the vector. The effect of this temperature restriction in relation to the geographical distribution of the two species is discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Onchocerciasis in British cattle: a study of the transmission ofOnchocercasp. in North Wales

McCall

Trees

1993

J. Helminthol.

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“…In this paper, the equipment used is described and the results recorded of a series of experiments made during the late summer of 1980 using a British species, S. ornatum Meigen s.l. This species is the vector of the nematode Onchocerca gutturosa, a parasite of cattle (Eichler, 1971;Eichler & Nelson, 1971).…”

Section: Introductionmentioning

confidence: 99%

Studies on the flight of black-flies (Diptera: Simuliidae). I. Flight performance ofSimulium ornatumMeigen

Cooter¹

1982

Bull. Entomol. Res.

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The flight performance of Simulium ornatum Mg. s.l. was measured under laboratory conditions using a simple flight mill. Males and unmated females were flown and the duration, distance and average speed of flight were recorded for adults fed on water only, sucrose, blood & water, or blood & sucrose. On 91% of all test occasions sucrose-fed insects flew but 25% of those on water only did not fly. Feeding flies on 10% sucrose solution markedly improved both willingness to fly and flight performance, and under these conditions maximum duration, distance and average speed recorded were 4.9 h, 4-2 km and 2-84 km/h, respectively. The ratio of average to maximum speed was 0"631 for females and 0 -610 for males, with absolute maximum speeds of 3"19 and 2-99 km/h, respectively. Duration and distance flown were well-correlated, speed being the least variable aspect of flight performance measured. The distributions of flight duration and distance flown were skewed such that few insects made long flights. Mean flight performance at different ages was measured; unmated females appeared to retain a high level of willingness to fly throughout the age-range tested (up to 33 days). The longest recorded flight (5.3 h) was made by a female during an overnight experiment. The implications for long-range flight movements by simuliids are discussed.

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“…In this study, no statistical difference was observed in the infection in male and female camels; however, older camels were infected more frequently which could be due to a longer exposure to the vector. In contrast, no increase in parasite density with age was recorded in O. gutturosa infection in cattle, which is attributed to the immune reaction of the host species to Onchocerca infection [29].…”

Section: Discussionmentioning

confidence: 76%

Scanning electron microscopy of Onchocerca fasciata (Filarioidea: Onchocercidae) adults, microfilariae and eggs with notes on histopathological findings in camels

et al. 2020

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Background: Onchocerca fasciata is a prevalent filarial species in camelids of Asia and Africa forming nodules in the skin of dromedary and Bactrian camels. In spite of recent advances in the biology and epidemiology of this nematode species, a relatively scant number of studies have focussed on the morphology of this parasite. The main objective of this study was to describe morphological characteristics of adults, microfilariae and eggs of O. fasciata by scanning electron microscopy (SEM), staining and histology. Methods: From April 2016 to March 2017 dromedary camels (n = 456) were inspected for infection with O. fasciata in a slaughterhouse in Kerman (south of Iran). Adult worms in nodules were isolated by digestion of nodules in collagenase and used for SEM. Skin nodules were also fixed, sectioned and stained with hematoxylin and eosin for histopathology. Skin microfilariae that were isolated from tissues surrounding the nodules were confirmed as O. fasciata by sequencing of the cytochrome c oxidase subunit 1 (cox1) and 12S rRNA genes and used for SEM and Giemsa staining. Results: Single or multiple O. fasciata nodules (1.2-2.2 cm in diameter and 507-845 mg in weight) were found in 30.3% of the examined camels. SEM analysis helped identify 18 papillae in the caudal region of the male. Discontinuous longitudinal cuticular crests were observed in the posterior region of the male. In female nematodes, the ridges had a rounded shape with a height/width ratio of 7/16 in longitudinal sections. Unsheathed skin microfilariae with a rounded anterior extremity measured 210.7 × 2.5 μm on average. Developed eggs containing microfilariae measured 35.9 × 31.0 μm and their smooth shell surface had characteristic tongue-like appendages. In addition to inflammatory reactions surrounding the parasites, accumulation of intracellular ceroid pigment, golden-yellow to brown in colour, was observed within macrophages upon histopathological examination. Conclusions: We found longitudinal crests on the surface of the posterior region of the male nematode. Measurements of the main morphological features of microfilariae and eggs, and the shape index of ridges (height/width) in female nematodes are described for the first time.

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Studies on Onchocerca gutturosa (Neumann, 1910) and its Development in Simulium ornatum (Meigen, 1818). I. Observations on O.gutturosa in cattle in South-East England

Cited by 42 publications

References 11 publications

Onchocerciasis in British cattle: a study of the transmission ofOnchocercasp. in North Wales

Onchocerciasis in British cattle: a study of the transmission ofOnchocercasp. in North Wales

Studies on the flight of black-flies (Diptera: Simuliidae). I. Flight performance ofSimulium ornatumMeigen

Scanning electron microscopy of Onchocerca fasciata (Filarioidea: Onchocercidae) adults, microfilariae and eggs with notes on histopathological findings in camels

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