FLOTAC: An improved method for diagnosis of lungworm infections in sheep

Lungworms in ruminants from Brazil: A retrospective epidemiological study over four decades

Lungworms such as Dictyocaulus spp. in cattle and small ruminants, and Muellerius capillaris and Protostrongylus rufescens in small ruminants are important pathogens, causing respiratory disease in these livestock species. Despite their veterinary importance, lungworms of livestock have been poorly studied in certain regions of the world, including Brazil. Therefore, much of their epidemiology and economic impacts on production remain unknown. This article aims to provide a comprehensive overview of the historical and current data published on lungworm infection of domestic ruminants in Brazil. This review consisted of a comprehensive search of technical and scientific publications between January 1980 to December 2020, using online sources such as PubMed, Google Scholar and Scielo. Twenty-four articles published over the last 40 years reporting lungworms exclusively in cattle (n = 16), goats (n = 6) and sheep (n = 1) in Brazil were included. In addition, a study (n = 1) with both goats and sheep were also utilized. Overall, 12 studies were based only on post-mortem examination, five in the detection of specimens in fecal samples, and seven were based on fecal analysis followed by post-mortem examination. Out of all studies, 66.7% (n = 16) articles registered D. viviparus, 4.2% (n = 1) D. filaria, 8.3% (n = 2) P. rufescens, 16.7% (n = 4) M. capillaris, and 4.2% (n = 1) co-infection by D. filaria and M. capillaris. The existence of suitable environmental conditions, as well as intermediate and definitive hosts in Brazil contribute for the survival and development of these nematode species. The majority of the reports of lungworms originate from the Southern and Southeastern regions of the country, whose mild temperatures likely contribute to their occurrence. Finally, lungworms of ruminants have been reported over the past four decades in Brazil, but most of the information was obtained at post-mortem examination. Therefore, further studies to investigate epidemiological aspects in different hosts and regions of the country are needed.

Quantitative Monitoring of Selected Groups of Parasites in Domestic Ruminants: A Comparative Review

Parasites have had a significant impact on domestic ruminant health and production for a long time, but the emerging threat of drug resistance urgently requires an improved approach to parasite monitoring and control activities. The study reviewed the international literature to analyze the different proposals for the sampling approach and the quantitative estimation of parasite burdens in groups of animals. Moreover, the use of thresholds to decide when and which animal to treat was also investigated. The findings of the study highlighted the presence of a wide-ranging literature on quantitative monitoring for gastrointestinal nematodes (GIN), while more limited data were found for coccidia, and no specific indications were reported for tapeworms. Concerning liver flukes, bronchopulmonary nematodes (BPN) and permanent ectoparasites (lice and mange mites), the diagnostic process is usually aimed at the detection of the parasite rather than at the burden estimation. The main research gaps that need further investigation were also highlighted. For some groups of parasites (e.g., GIN and coccidia) the quantitative approach requires an improved standardization, while its usefulness needs to be confirmed for others (e.g., BPN and lice). The development of practical guidelines for monitoring is also encouraged.

Helminths of Wild Boar ( Sus scrofa) in the Calabrian Region of Southern Italy

In Calabria, as in other Italian regions, the wild boar (Sus scrofa) population has increased considerably in the last few years. The presence of this wild ungulate, a huntable species, was detected throughout this region. Wild boars are a host for many endoparasites, some of which are zoonotic. Our aim was to acquire data on the prevalence endoparasites in wild boar in the region of Calabria, Italy, where such information is limited. We used 60 wild boars culled during the 2014-15 hunting season. We used FLOTAC dual techniques for fecal microscopic exams, as well as qualitative and quantitative microscopic examination with a sensitivity level of 2 eggs/g of feces. The research has underlined the remarkable diffusion of gastrointestinal helminths, particularly Ascaris suum, in wild boar of the areas of Sila and Presila in the province of Catanzaro, Calabria.

Flotation techniques (FLOTAC and mini-FLOTAC) for detecting gastrointestinal parasites in howler monkeys

Background

Analyses of environmental correlates of the composition of gastrointestinal parasite communities in black howler monkeys (Alouatta pigra) have been hindered by inadequate calibration techniques of detection and quantification methods of the parasites. Here we calibrate samples and compare the likelihood of parasite detection using two flotation techniques, FLOTAC and Mini-FLOTAC, and compare flotation solution, preservation method and dilution ratio for egg detection and counts of the most common parasites (Controrchis spp. and Trypanoxyuris spp.) in howler monkeys.

Results

For samples preserved in 5% formalin, the Mini-FLOTAC technique was the best option for qualitative and quantitative copro-microscopic analysis. This technique displays an 83.3% and 100% detection of Controrchis spp. and Trypanoxyuris spp. infections, respectively. For the trematode Controrchis spp., more eggs per gram of feces (EPG) were recorded with the flotation solution (FS) #7 (zinc sulfate; specific gravity SG = 1.35) at 1:20 and 1:25 dilution than other methods. By contrast, for the nematode Trypanoxyuris spp., the best results were recorded with FS1 (sucrose and formaldehyde; SG = 1.20) at 1:10 dilution.

Conclusions

We recommend the Mini-FLOTAC technique for general use with parasite analysis on frugivore/folivores like the howler monkey, especially if many samples are analyzed. The technique has a high detection rate and the best EPG counts, allowing the qualitative and quantitative analysis of parasite load among the species or populations without the need for specialized equipment.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2532-7) contains supplementary material, which is available to authorized users.

Lungworms in Alpine ibex (Capra ibex) in the eastern Alps, Italy: An ecological approach

Host-parasite relationships have been frequently investigated in mountain dwelling ungulates, though mostly focusing on gastrointestinal nematodes. On the contrary, very few studies were conducted on broncopulmonary nematodes, which may result in severe parenchymal lesions and act as predisposing factor for multifactorial pneumonia. The epidemiological and ecological features of lungworms infecting an Alpine ibex population in the Eastern Alps, Italy, were non-invasively investigated by means of a modified Baermann technique with an original quantitative methodology. Out of a total of 269 samples collected monthly from July to November 2013 and from July to October 2014, 212 (78.8%) were positive for Muellerius and 26 (9.7%) for Protostrongylus, whereas Neostrongylus and Cystocaulus were less prevalent (4.1% and 0.7%, respectively). None of the investigated samples tested positive for dictyocaulids. The genus Muellerius showed the highest larval output intensity (134.2 L1/g), followed by Protostrongylus with 33.8 L1/g. A contrasting age-related pattern of Muellerius and Protostrongylus was revealed, with the former significantly more prevalent and abundant in adult animals, while the latter in kids. Due to the limited accessibility of the study area during winter and spring, it was difficult to describe clear seasonal trends in larval output, although Muellerius showed a minimum in the late summer and a rise in the autumn. The newly developed diagnostic method showed a fair repeatability, thus representing an interesting tool to investigate the ecology of lungworms in protected species, such as the A. ibex. Based on results, ibex in the Marmolada massif seem to have an ecologically stable relationship with their lungworm community.

COMPARISON OF MODIFIED FLOTAC AND BAERMANN TECHNIQUES FOR QUANTIFYING LUNGWORM LARVAE IN FREE-RANGING BIGHORN SHEEP (OVIS CANADENSIS) FECES, MONTANA, USA

Lungworms are important parasites of wildlife and host infection status is often evaluated using coprologic techniques, most commonly the Baermann method. Recently, the FLOTAC® has emerged as a new tool for diagnosing lungworm infections, and methodologic comparison studies in domestic species suggest that this method outperforms many other established techniques. We compared a modified FLOTAC with the beaker-modified (bm)-Baermann to evaluate the relative performance of the two techniques for counting lungworm larvae in bighorn sheep (Ovis canadensis) feces. Both methods generated equivalent larval counts and both were highly repeatable. The major difference between the two methods was that the FLOTAC was poorer at detecting mixed infections. The ultimate choice between using the FLOTAC and bm-Baermann methods for quantifying lungworm larvae in wildlife studies may depend on the specific nature of the research questions being addressed, balanced by practical constraints.

Tracking year-to-year changes in intestinal nematode communities of rufous mouse lemurs (Microcebus rufus)

While it is known that intestinal parasite communities vary in their composition over time, there is a lack of studies addressing how variation in component communities (between-hosts) manifests in infracommunities (within-host) during the host lifespan. In this study, we investigate the changes in the intestinal parasite infracommunities in wild-living rufous mouse lemurs (Microcebus rufus) from Ranomafana National Park in southeastern Madagascar from 2010 to 2012. We used high-throughput barcoding of the 18S rRNA gene to interrogate parasite community structure. Our results show that in these nematode communities, there were two frequently occurring putative species and four rarer putative species. All putative species were randomly distributed over host individuals and they did not occur in clear temporal patterns. For the individuals caught in at least two different years, there was high turnover of putative species and high variation in fecal egg counts. Our study shows that while there was remarkable variation in infracommunities over time, the component community was relatively stable. Nevertheless, the patterns of prevalence varied substantially between years in each component community.

Helminth control in kennels: is the combination of milbemycin oxime and praziquantel a right choice?

Background

Kennel dogs are at the high risk of infections with intestinal and extra-intestinal helminths. Therefore, regular parasitological surveillance, appropriate treatment strategies and high quality standard of hygiene are required to guarantee the health and welfare of kennel dogs. The aim of the present study was to evaluate the efficacy of helminth control in kennels using different broad-spectrum anthelmintics that are routinely used in canine veterinary practice. Particular attention was given to the field efficacy and ease-of-use of each product.

Methods

The study was conducted in 3 public kennels in the Campania region (southern Italy). Eighteen boxes from each of the three kennels were selected for treatment based on faecal egg counts (FECs) at Day −30. The treatments were conducted using tablets containing combinations of: i) milbemycin oxime and praziquantel (Milbemax®); ii) pyrantel embonate, febantel and praziquantel (Drontal Plus Flavour®), and; iii) pyrantel pamoate, oxantel pamoate and praziquantel (Nemex® POP). All dogs were treated on Day 0 and sampled on Days 0, 7, 14 and 21 for copromicroscopic analyses. The FLOTAC dual technique on pooled samples was used with efficacy determined by reduction in FECs.

Results

At Day −30 intestinal nematodes (hookworms, Toxocara, Trichuris) and cestodes (Dypilidium caninum) were found. Milbemax® showed 100% efficacy against all the helminths in all the kennels. Drontal Plus Flavour® was 100% effective against hookworms in all the kennels but gave lower efficacy against T. canis (range = 97.1-100%) and T. vulpis (range = 95.6-100%). Nemex® POP was also 100% effective against hookworms in all kennels but less effective against T. canis (range = 95.7-100%) and T. vulpis (range = 95.7-100%). All three drugs were 100% effective against D.caninum.

Conclusions

Milbemax®was fully effective against all the helminthes and was palatable and ease-of-use for all the dogs. It is the optimum choice for the treatment and prevention of helminth infections in kennel dogs under field conditions.

Comparison of faecal techniques including FLOTAC for copromicroscopic detection of first stage larvae of Angiostrongylus vasorum

Angiostrongylus vasorum is a metastrongylid nematode that resides in the pulmonary arteries and the right heart chambers. In dogs, infection results in respiratory, bleeding and neurological disorders and further clinical signs. In the present study, FLOTAC was evaluated for the detection of first-stage larvae (L1) of A. vasorum in canine faecal samples. This technique is based on the counting of parasitic stages (eggs, larvae, oocysts and cysts) in chambers after spinning of faecal samples onto a surface. In a first step, nine flotation solutions were evaluated using faeces of two experimentally infected dogs. Zinc sulphate (specific gravity (s.g.) 1.2) and zinc sulphate plus potassium iodomercurate (s.g. 1.45) gave good results. However, with the latter technique, the larvae were slightly deformed. Subsequently, FLOTAC, using zinc sulphate, was compared through a randomisation technique with McMaster, flotation in tube and Baermann-Wetzel technique. The mean larvae per gramme (LPG) obtained by the FLOTAC for both dogs was significantly higher (P < 0.05) than those obtained by the other three techniques (the means of the other techniques all lie below the 95% CI of the mean LPG of the FLOTAC technique). In addition, the FLOTAC results were consistent across replicates with only Poisson (or random) variation between individual replicates. The other techniques appear to be less consistent with evidence of extra-Poisson variation in at least one of the two dogs across the replicates within each technique. The FLOTAC technique may contribute to an improvement of the ability to diagnose canine lungworm infections and represent a valuable alternative for larval counting of A. vasorum in faecal samples, especially following transport or storage where there may be limited larvae viability, and larval migration techniques cannot be used.