Evaluation of techniques for detection of small trematode eggs in faeces of domestic animals

Anh, Nguyễn Thị Lan; Phuong, Nguyen Thi; Ha, Giang Hoang; Thu, Luong To; Johansen, Maria Vang; Murrell, Darwin; Thamsborg, Stig Milan

doi:10.1016/j.vetpar.2008.05.021

Cited by 24 publications

(17 citation statements)

References 11 publications

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“…Climatic factors are known to delimit suitable living areas for intermediate hosts, thereby conditioning the spatial distribution of parasitic diseases [13], [14]. Lower risk in altitude might relate to local features that do not meet ecological requirements of the first intermediate host snails of the genus Bithynia [46]. However, infection risk was significantly associated with distance to water bodies and rainfall amount only, and hence our data do not support an association between ecological requirements of the snails and environmental features.…”

Section: Discussioncontrasting

confidence: 64%

Spatial Distribution of, and Risk Factors for, Opisthorchis viverrini Infection in Southern Lao PDR

et al. 2012

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Background Opisthorchis viverrini is a food-borne trematode species that might give rise to biliary diseases and the fatal cholangiocarcinoma. In Lao PDR, an estimated 2.5 million individuals are infected with O. viverrini, but epidemiological studies are scarce and the spatial distribution of infection remains to be determined. Our aim was to map the distribution of O. viverrini in southern Lao PDR, identify underlying risk factors, and predict the prevalence of O. viverrini at non-surveyed locations.MethodologyA cross-sectional parasitological and questionnaire survey was carried out in 51 villages in Champasack province in the first half of 2007. Data on demography, socioeconomic status, water supply, sanitation, and behavior were combined with remotely sensed environmental data and fed into a geographical information system. Bayesian geostatistical models were employed to identify risk factors and to investigate the spatial pattern of O. viverrini infection. Bayesian kriging was utilized to predict infection risk at non-surveyed locations.Principal FindingsThe prevalence of O. viverrini among 3,371 study participants with complete data records was 61.1%. Geostatistical models identified age, Lao Loum ethnic group, educational attainment, occupation (i.e., rice farmer, fisherman, and animal breeder), and unsafe drinking water source as risk factors for infection. History of praziquantel treatment, access to sanitation, and distance to freshwater bodies were found to be protective factors. Spatial patterns of O. viverrini were mainly governed by environmental factors with predictive modeling identifying two different risk profiles: low risk of O. viverrini in the mountains and high risk in the Mekong corridor.Conclusions/SignificanceWe present the first risk map of O. viverrini infection in Champasack province, which is important for spatial targeting of control efforts. Infection with O. viverrini appears to be strongly associated with exposure to the second intermediate host fish, human behavior and culture, whereas high transmission is sustained by the lack of sanitation.

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Section: Discussioncontrasting

confidence: 64%

Spatial Distribution of, and Risk Factors for, Opisthorchis viverrini Infection in Southern Lao PDR

et al. 2012

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“…One limitation of our study is that the use of 2 different methods to obtain prevalence data from humans (5) and domestic animals may have introduced a bias when comparing the relative contributions of the eggs to the environment. However, the Kato-Katz method and our method were evaluated as reliable and the most suitable methods for detection of eggs in human and domestic animal studies, respectively (8,15). The prevalence and species diversity of FZT in dogs, cats, and pigs in Vietnam (H. pumilio, H. taichui, H. yokogawai, Echinochasmus japonicus, E. perfoliatus, Echinostoma cinetorchis, and Centrocestus formosanus) may represent an emerging problem.…”

Section: Discussionmentioning

confidence: 98%

“…Fecal samples (5 g each) were examined by a combined fi ltration, sedimentation, and centrifugation method described by Willingham et al (7) and Anh et al (8). For each sample, trematode eggs were counted 3 times, the sum of which was equivalent to eggs per gram (epg).…”

Section: Study Design Sampling and Laboratory Analysismentioning

confidence: 99%

Animal Reservoir Hosts and Fish-borne Zoonotic Trematode Infections on Fish Farms, Vietnam

Anh¹,

Phuong²,

Murrell³

et al. 2009

Emerg. Infect. Dis.

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Fish-borne zoonotic trematodes (FZT) pose a risk to human food safety and health and may cause substantial economic losses in the aquaculture industry. In Nghe An Province, Vietnam, low prevalence of FZT for fi sh farmers but high prevalence for fi sh indicate that reservoir hosts other than humans may play a role in sustaining transmission. To determine whether domestic animals may be reservoir hosts, we assessed prevalence and species composition of FZT infections in dogs, cats, and pigs in a fi sh-farming community in Vietnam. Feces from 35 cats, 80 dogs, and 114 pigs contained small trematode eggs at 48.6%, 35.0%, and 14.4%, respectively; 7 species of adult FZT were recovered from these hosts. These results, combined with data from previous investigations in this community, imply that domestic animals serve as reservoir hosts for FZT and therefore must be included in any control programs to prevent FZT infection in humans. In Asia, fi sh-borne zoonotic trematodes (FZT), including liver and intestinal fl ukes, are widely reported (1-3). FZT not only pose risks to food safety and human health but also may cause substantial economic losses in the aquaculture industry, resulting from to restrictions on exports and reduced consumer demand because of food safety concerns (4). A range of mammals and birds serve as defi nitive hosts for FZT (2). Although information on infection levels and species distribution in humans and fi sh is becoming increasingly available, similar information for reservoir hosts such as wild and domestic animals and fi sh-eating birds is scarce (1).Recent studies conducted in Nghe An Province, a major area for freshwater aquaculture in Vietnam, found prevalence of FZT in humans to be low (0.6%) and prevalence in fi sh from farms to be high (>35%) (5,6). These fi ndings suggest that reservoir hosts other than humans play a major role in sustaining transmission of FZT in this community. We therefore investigated the role of the domestic animals on these fi sh farms. We determined prevalence and species composition of FZT infections in dogs, cats, and pigs in the community and analyzed potential risk factors for the transmission of FZT to animals and animals' role in sustaining FZT infections in cultured fi sh. Materials and Methods Study Design, Sampling, and Laboratory AnalysisThe study was conducted in November 2005 in Nghe An Province, northern Vietnam (Figure 1), in fi sh-farming households previously investigated for human and fi sh FZT infections (5,6). From a total of 1,281 households, 50 were randomly selected in proportion to farm numbers in 5 districts: Hung Nguyen (n = 8), Nam Dan (n = 15), Yen Thanh (n = 9), Thanh Chuong (n = 10), and Tan Ky (n = 8). Another fi sh farm previously found to have cases of FZT in humans (5) was included, yielding a total of 51 fi sh-farming households in the study.

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“…However, the Kato-Katz method is still not widely used in the diagnosis of animal trematodiasis. Anh et al (2008) used three sensible diagnostic tests, including the Kato-Katz method, for the identification of small trematode eggs (<50 µm) in fecal samples of domestic animals. In addition to the Kato-Katz method, formalin-ether sedimentation and a more laborious method combining filtration, sedimentation, and centrifugation (the Danish Bilharziasis Laboratory [DBL] method) were evaluated.…”

mentioning

confidence: 99%

“…In their study, the sensitivity of the techniques of detection of small trematode eggs was the same in cats as in pigs, whereas the Kato-Katz method was slightly less sensitive in dogs. Anh et al (2008) recognized that this last observation might be due to the amounts of feces evaluated being small and/or the lack of a washing procedure in the technique making the detection of eggs on the slide more difficult. Moreover, the influence of the different number of slides analyzed and the use of serial daily samples to increase the sensitivity of the diagnostic methods was not considered.…”

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confidence: 99%

Evaluation of Kato-Katz and spontaneous sedimentation methods for the diagnosis of platynosomiasis in Neotropical primates

Mati

Pinto

Melo

2015

Rev. Bras. Parasitol. Vet.

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Platynosomiasis is a parasitic infection reported in non-human primates, including marmosets, and is frequently difficult to diagnose. In this study, the Kato-Katz method and the spontaneous sedimentation method were evaluated for their usefulness in identifying Platynosomum eggs in fecal samples from Callithrix penicillata that naturally harbor Platynosomum illiciens. Spontaneous sedimentation allowed the diagnosis of 41.7% (5/12) and 66.7% (8/12) of infected marmosets from one and three slides, respectively, prepared from the same fecal sample. The examination of a single Kato-Katz thick smear detected 83.3% (10/12) of infection cases. The analysis of feces on three different days increased the rate of diagnosis, since 75% (9/12) and 100% (12/12) of the primates with platynosomiasis were identified using serial spontaneous sedimentation (3 slides/day) and the Kato-Katz method, respectively. The mean number of Platynosomum eggs per gram of feces determined via the Kato-Katz method was 71.7 (8-240). The spontaneous sedimentation method when performed in series is acceptable for the diagnosis of platynosomiasis. However, the Kato-Katz method, which was here used for the first time to detect this infection, has a higher diagnostic sensitivity and the advantage that a quantitative analysis of the eggs released in the host feces is possible.Keywords: Fecal parasitological diagnosis, platynosomiasis, Platynosomum, marmosets, spontaneous sedimentation, Kato-Katz thick smear. ResumoA platinossomose é uma infecção parasitária relatada em primatas não-humanos, inclusive saguis, cujo diagnóstico é frequentemente difícil. Neste estudo, os métodos de sedimentação espontânea e Kato-Katz foram avaliados quanto à sua utilidade na identificação de ovos de Platynosomum em amostras fecais de Callithrix penicillata naturalmente albergando Platynosomum illiciens. A sedimentação espontânea permitiu o diagnóstico de 41,7% (5/12) e 66,7% (8/12) dos saguis infectados a partir da análise de uma e três lâminas, respectivamente, preparadas de uma mesma amostra fecal. O exame de uma única lâmina de Kato-Katz detectou 83,3% (10/12) dos casos de infecção. A análise de fezes em três dias diferentes aumentou as taxas de diagnóstico, uma vez que 75% (9/12) e 100% (12/12) dos primatas que apresentaram a platinossomose foram identificados, usando-se a sedimentação espontânea (três lâminas/dia) e o Kato-Katz em série, respectivamente. O número médio de ovos de Platynosomum por g de fezes, determinado através do método de Kato-Katz, foi de 71,7 (8-240). O método de sedimentação espontânea, quando realizado em série, é aceitável para o diagnóstico da platinossomose. Entretanto, o método de Kato-Katz, o qual foi pela primeira vez usado para se detectar essa infecção, mostrou uma maior sensibilidade diagnóstica, com a vantagem de que é possível uma análise quantitativa dos ovos liberados nas fezes do hospedeiro.Palavras-chave: Diagnóstico parasitológico fecal, platinossomose, Platynosomum, saguis, sedimentação espontânea, Kato-Katz.

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Evaluation of techniques for detection of small trematode eggs in faeces of domestic animals

Cited by 24 publications

References 11 publications

Spatial Distribution of, and Risk Factors for, Opisthorchis viverrini Infection in Southern Lao PDR

Spatial Distribution of, and Risk Factors for, Opisthorchis viverrini Infection in Southern Lao PDR

Animal Reservoir Hosts and Fish-borne Zoonotic Trematode Infections on Fish Farms, Vietnam

Evaluation of Kato-Katz and spontaneous sedimentation methods for the diagnosis of platynosomiasis in Neotropical primates

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