Cristina Santos Sotomaior

Resistance of gastrointestinal nematodes to anthelmintics in sheep (Ovis aries)

O teste de reducao da contagem de ovos de helmintos por grama de fezes (FECRT) foi usado para testar a eficiencia dos antihelminticos em 42 propriedades produtoras de ovinos, em cinco diferentes regioes no Estado do Parana, Brasil. O estudo foi realizado entre Julho 1996 a Julho de 2000. Foram avaliados animais com infeccao natural. Cinco drogas foram usadas so ou em combinacao (benzimidazole, imidazothiazole, ivermectin, milbemicina e closantel). Resultados mostraram que a prevalencia de resistencia foi alta para todos os antihelminticos avaliados: 88.1% para benzimidazoles (oxfendazole), 78.6% para ivermectin, 56.4% para closantel, 38.7% para closantel + oxfendazole, 38% para levamisole, e 23.6% para moxidectin. Havia resistencia multipla em todas fazendas estudadas. Na identificacao das larvas de helmintos recuperadas das culturas de fezes apos o tratamento verificou-se que maioria pertenciam a Haemonchus sp. e Trichostrongylus sp. O fracasso das drogas existentes no mercado em combater a verminose e considerado um assunto importante. No presente artigo algumas sugestoes sao discutidas para melhorar a situacao, elas incluem uma mudanca de atitude em relacao ao uso indiscriminado de antihelminticos.

Sensitivity and specificity of the FAMACHA © system in Suffolk sheep and crossbred Boer goats

Sheep and goats are the species of farm animal with the highest growth rate in Paraná State. The main problems facing Paraná State flocks are gastrointestinal parasites and anthelmintic resistance. One of the newest resources used to slow down the development of anthelmintic resistance is the FAMACHA(©) system, a selective method useful for controlling gastrointestinal verminosis in small ruminants. The purpose of the present research was to evaluate the sensitivity and specificity of the FAMACHA(©) system in sheep and goats and to compare the results for both species. The conjunctivae of 83 Suffolk ewes and 60 adult crossbred Boer does were evaluated by the same trained person using the FAMACHA(©) system. The packed cell value (PCV) served as the gold standard for clinical FAMACHA(©) evaluation. To calculate the sensitivity and specificity of the FAMACHA(©) system, different criteria were adopted in turn: animals classified as FAMACHA(©) (F(©)) 4 and 5, or 3, 4 and 5, were considered to be anemic (positive test), and animals classified as F(©)1, 2 and 3, or 1 and 2 were considered to be non-anemic (negative test). Three standard values of PCV, namely ≤19%, ≤18% or ≤15%, were used to confirm anemia. At all cut-off levels, the sensitivity increased if F(©)3 animals were included as being anemic. However, changes in levels of sensitivity were associated with reciprocal changes in specificity. The sensitivity was higher for sheep than for goats, excepting when the criteria included PCV≤18 and F(©)3, F(©)4 and F(©)5 were considered positive. In contrast, the specificity was always lower in sheep for any criteria adopted. Other than in goats, using the ≤15 cut-off level for sheep, it is possible to opt not to drench the animals that were shown to be F(©)3 because the sensitivity is still high, indicating that few animals that should have been drenched were overlooked. In goats, in contrast, the low sensitivity at all cut-off levels made it too risky to leave F(©)3 animals undrenched. Even though the number of correct treatments for goats was always higher than that for sheep, the opposite was true for the kappa index for all the criteria tested. Therefore, the FAMACHA(©) system is suitable for the identification of anemic animals of both species. It is necessary that all small ruminants classified as FAMACHA(©) level 3 are also treated to increase the sensitivity of the method.

Lack of efficacy of monepantel against Trichostrongylus colubriformis in sheep in Brazil.

Multiple drug resistance of nematodes against anthelmintics has become one of the most important economic problems in sheep production worldwide. The aim of this experiment was to evaluate the efficacy of monepantel (2.5mg/kg) against gastrointestinal nematodes in fecal egg count reduction test (FECRT) and controlled efficacy test (CT) in naturally infected sheep. We used 30 sheep for the FECRT and 20 sheep for the CT, equally divided into control and treated groups. In the FECRT, the reduction was 98%. Larval identification of pre-treatment coprocultures revealed 100% Haemonchus spp. for both control and treated groups. Post-treatment culture of treated sheep was 100% Oesophagostomum spp., but only few larvae were recovered. In the control group, they were 99% Haemonchus spp and 1% Oesophagostomum spp. larvae. Based on the FECRT, Haemonchus spp. was considered susceptible to monepantel. The efficacy of monepantel in the CT against Haemonchus contortus and Trichostrongylus axei was 100% and against Cooperia curticei was 99.7%. For Trichostrongylus colubriformis, the efficacy was -21.5%. In both treated and untreated animals, Oesophagostomum columbianum was recovered from the large intestines. Based on FECRT and CT and in accordance with WAAVP standards, monepantel was ineffective against T. colubriformis and O. columbianum, but effective against H. contortus, T. axei and C. curticei in the studied flock.

Assessment of a hands-on method for FAMACHA© system training.

The FAMACHA(©) system is a method for selective anthelmintic treatment comprising early detection of haemonchosis in sheep and goats. In order to evaluate the hands-on training methodology and the learning level of the participants, we analyzed data from 30 training events involving 47 training classes conducted in the State of Paraná, Brazil, from July/2009 to May/2011, during which period a total of 1004 participants did 20,080 FAMACHA(©) classifications. In the practical training sessions, each participant individually evaluated 20 animals with known haematocrit values. Every participant per training event was given a unique number, whereupon each of the animals in a given event was FAMACHA(©) classified by all the trainees involved, in the same trainee number sequence. After each consecutive animal had been evaluated by every one of the participants, its haematocrit and corresponding FAMACHA(©) category were announced before the next animal was presented. The number of persons in training, which ranged from 5 to 39 per session, did not significantly affect the average error of the groups of participants involved (p>0.05). The average error in the classification of the first animal on a scale with a perfect score of zero was 2.5, significantly greater than the error of 0.56 of the twentieth one (p<0.05), indicating an inverse relationship between the error and the cumulative number of animals already evaluated by each trainee involved, with the reduction in mean error per animal in a given training event found by linear regression to be 0.0713. When the same animal was assessed twice in the same training event, the average error of the second evaluation (1.05) was significantly lower than the 1.70 of the first (p<0.05). While the total of 686 sheep used in the training events (73%) was considerably larger than the corresponding number of 254 goats (27%), the average statistical errors, respectively, 1.34 and 1.23, were not significantly different (p>0.05). Similarly, the average errors in FAMACHA(©) classification were not significantly influenced by the occupation or gender of the participants, nor whether there were animals in all five FAMACHA(©) categories or only in categories 1, 2, 3 and 4 per training event (p>0.05).

Toxoplasma gondii in goats from Curitiba, Paraná, Brazil: risks factors and epidemiology

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, a protozoan with wide geographical distribution and minimal parasitic specificity that affects many species of wild and domestic animals. In livestock, especially in small ruminants like goats, toxoplasmosis can cause abortion and the birth of weak animals, leading to economic losses to farmers, and is a major source of human infection. This is a seroepidemiological study of toxoplasmosis in goats in the state of Paraná, Brazil. Sera from 405 goats from the metropolitan mesoregion of Curitiba, eastern state, were tested by the enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence antibody test (IFAT). Information on properties and goat characteristics was also collected using questionnaires. The prevalence of toxoplasmosis was 39.41 and 35.96% by ELISA and IFAT, respectively. T. gondii antibody prevalence increased with age. The risk factors for T. gondii infection in goats were: age over one year; exposure to cats, type of management and purpose of breeding. Other epidemiological factors and relevant control measures are discussed in the current study.

FAMACHA© system assessment by previously trained sheep and goat farmers in Brazil.

The aim of this study was to evaluate the degree of adoption and the correct use of the FAMACHA© system amongst sheep and goat farmers trained in a previous hands-on course. A survey was carried out with 1375 people who received FAMACHA© training from July 2009 to May 2011 in Paraná State, Brazil. The survey was conducted from March 2012 to May 2013. Firstly, a questionnaire was applied with specific questions for farmers about their anthelmintic (AH) treatment practices before and after the FAMACHA© training. In a second step, eight of the questionnaire respondents classified as sheep or goat farmers were contacted for an in loco visit during which the application of the FAMACHA© system was evaluated in the respective farms and blood samples were collected from 20 animals to calculate sensitivity and specificity. A total of 124 farmers responded the questionnaire (9% of project participants). Farmers accounted for 48.4% of total responses. Half of these farmers (51.6%) reported losses related to parasites in their property before the training. Antiparasitic treatments, at fixed intervals, were responsible for 93.1% of deworming practices before the training project. FAMACHA© was unknown for 51.7% of the respondents, and 31% knew the chart, but did not use it. After the project, 69% had adopted the system and 83% assessed the animals at regular intervals. However, 18.9% did not evaluate all animals. During the in loco visits, problems reported included the incorrect exposure of the ocular mucosa (50% of farmers) and not using the chart (87.5%). Also, 62.5% did not keep records of the FAMACHA© assessment history of the flock. However, sensitivity was 100%, with 0% false negatives. We conclude that, amongst farmers who adopted the system, despite some methodological errors regarding its use, the objectives were met in terms of reducing the number of anthelmintic treatments and providing anemic animals with AH treatment. Trained farmers seemed to require technical guidance post-training to promote effective use of the FAMACHA© system.

Treponemes Detected in Digital Dermatitis Lesions in Brazilian Dairy Cattle and Possible Host Reservoirs of Infection

ABSTRACT The main pathogenic treponemes causing bovine digital dermatitis were identified from 17 infected herds in southern Brazil for the first time in this study using PCR. We did not find a relationship between treponeme phylogroup composition and clinical classification. Treponema phagedenis was present in all lesions. Rumen fluid was implicated as a reservoir location for these pathogens.

FAMACHA© scores history of sheep characterized as resistant/resilient or susceptible to H. contortus in artificial infection challenge

With the aim of validating the FAMACHA(©) as a method for phenotypic selection of sheep resistant/resilient to gastrointestinal nematodes, 27 Suffolk ewes with known FAMACHA(©) score histories were experimentally infected with 25,000 larvae of Haemonchus contortus. From the day of infection (day 0) to 60 days post-infection, at intervals of 7-15 days, ewes were evaluated for packed cell volume (PCV) and fecal egg counts (FEC). A statistically significant increase (p<0.05) in FEC occurred between day 0 and day 60. PCV values showed a decrease (p<0.05) starting from day 21, compared to day 0. Based on the changes in FEC and PCV values from day 0 to day 60, 15 ewes (55.56%) were classified as susceptible (S) and 12 ewes (44.44%) as resistant/resilient (RR). A comparison of the average FEC after infection between susceptible (4487.6 eggs per gram-epg) and resistant/resilient (1317.9epg) ewes showed a significant difference (p<0.05) between the two groups. The difference in average PCV values after infection (24.8% and 30.3% for S and RR, respectively) was also significant (p<0.05). Data from 980 previous evaluations of FAMACHA(©) scores from the 27 ewes showed that 58.33% of the ewes classified as RR and 46.67% of the S group had a history of only F1 and F2 scores. In the RR group, only one animal (8.33%) had an F4 score, occurring one time out of the 61 evaluations of this ewe. In contrast, 40.0% of S group ewes had F4 and/or F5 scores. During the period of FAMACHA(©) score history that was evaluated, 69.56% of the total number of anthelmintic treatments in the flock were administered to ewes from group S. Since ewes with F4 and/or F5 scores during the FAMACHA(©) score time period were classified as susceptible during the experimental infection (with the exception of one ewe), we conclude that the FAMACHA(©) score history is a useful tool for the selection of ewes that are resistant/resilient, as well as for the identification of susceptible animals that should be culled.

Sensitivity and specificity of the FAMACHA© system in growing lambs

The FAMACHA© system is used for targeted selective treatment (TST) of small ruminants for the control of haemonchosis. The aim of this study was to evaluate the sensitivity and specificity of this system in growing lambs. Between 2015 and 2016, lambs aged 60-210 days on two sheep farms were evaluated at 15-day intervals using the FAMACHA© system (F1-F5), with analysis of hematocrit (Ht), counting of eggs per gram of feces, and larval culture. The sensitivity and specificity of the system were calculated according to two criteria: criterion 1, lambs classified as F4 or F5 were considered anemic (positive test) and those classified as F1, F2, or F3 were considered not anemic (negative test); and criterion 2, lambs classified as F3, F4, or F5 were considered anemic (positive test) and those classified as F1 and F2 were considered not anemic (negative test). Three gold standard Ht cutoff values were used to diagnose anemia, i.e., ≤22%, ≤18%, and ≤15%. In total, 1591 assessments were analyzed. The highest percentage of larvae in the fecal cultures was for Haemonchus spp., with an average of 78.5%. The sensitivity values found when F3 lambs were considered anemic were 13.9%, 30.8%, and 66.7%, respectively, for Ht cutoff values of ≤22%, ≤18%, and ≤15%. When F3 lambs were excluded, the maximum sensitivity was 14.9% and the specificity was 100% for all degrees of anemia using criterion 1. The FAMACHA© system had low sensitivity in growing lambs and should not be used alone for control of haemonchosis in young animals.

Corrigendum to “Sensitivity and specificity of the FAMACHA© system in Suffolk sheep and crossbred Boer goats” [Vet. Parasitol. 190 (2012) 114–119]

The authors reported an error in Table 2; the titles of the true-negative and true-positive columns are switched, and a corrected versionof Table 2 follows below.