Pathological alterations caused by Anoplocephala perfoliata infection in the ileocaecal junction of equids

Equine tapeworm infections in Italy: A nationwide coprological survey

Grazing horses are exposed to various intestinal helminths, with tapeworms being of major concern due to their potential pathogenicity. Few regional data are available in Italy on tapeworm infections in horses; therefore, the aim of this study was to investigate the prevalence of Anoplocephala spp. eggs over a nine-year period (2014-2023) in 12,056 faecal samples from horses living in all 18 continental Italian regions. Coprological examinations were performed using the Proudman and Edwards (1992) method using Sheather's sugar solution as the floatation medium. An overall prevalence of 3.7 % (452 horses positive) was observed. Sex, age class, presence of pasture and living area were significantly associated with Anoplocephala spp. infection (p < 0.05). The results of this large-scale study showed a low prevalence of Anoplocephala spp. as detected by coprological analysis. However, considering that this parasite is potentially pathogenic at relatively low worm burdens, it should always be considered in helminth control programs, especially in horses with access to pasture. Moreover, considering the low sensitivity of coprological methods for detecting cestode infections, antibody-based diagnostics methods such as serum or saliva ELISA testing could provide more accurate information regarding the presence of tapeworm infections in horses.

The Use of Innovative Diagnostics to Inform Sustainable Control of Equine Helminth Infections

Helminths are commonly found in grazing equids, with cyathostomin nematodes and the cestode Anoplocephala perfoliata being the most prevalent. Most horses harbour low burdens of these parasites and do not develop signs of infection; however, in a small number of animals, high burdens can accumulate and cause disease. Cyathostomins are associated with a syndrome known as larval cyathostominosis. This occurs when large numbers of larvae emerge from the large intestinal wall. This disease has a case fatality rate of up to 50%. A. perfoliata infection has been associated with various types of colic, with burdens of >20 worms associated with pathogenicity. Anthelmintic resistance is a serious problem in cyathostomins and is emerging in A. perfoliata. Control methods that reduce reliance on anthelmintics now need to be applied, especially as no new dewormer compounds are on the horizon. Sustainable control methods must employ diagnostics to identify horses that require treatment. Coprological tests (faecal egg counts, FECs) have been used for several decades to inform treatment decisions to reduce helminth egg shedding. These tests cannot be used to assess host burdens as FECs do not correlate with cyathostomin or A. perfoliata burdens. In the last decade, new tests have become available that measure parasite-specific antibodies, the levels of which have been shown to correlate with parasite burden. These tests measure antigen-specific IgG(T) and are available in serum (cyathostomin, A. perfoliata) or saliva (A. perfoliata) formats. Tests for other helminths have been developed as research tools and need to be translated to support equine clinicians in practice. A key element of sustainable control strategies is that diagnostics must be used in combination with management approaches to reduce environmental transmission of helminths; this will help limit the proportion of horses harbouring parasite burdens that need to be targeted by treatment. This manuscript provides a review of the development, performance and general utility of various diagnostic methods for informing equine helminth management decisions.

The anthelmintic efficacy of natural plant cysteine proteinases against the equine tapeworm, Anoplocephala perfoliata in vitro

Papaya latex has been demonstrated to be an efficacious anthelmintic against murine, porcine, ovine and canine nematode parasites, and even those infecting poultry, and it has some efficacy against rodent cestodes. The active ingredients of papaya latex are known to be cysteine proteinases (CPs). The experiments described in this paper indicate that CPs in papaya latex, and also those in pineapples, are highly efficacious against the equine cestode Anoplocephala perfoliata in vitro, by causing a significant reduction in motility leading to death of the worms. The susceptibility of A. perfoliata to damage by CPs was considerably greater than that of the rodent cestodes Hymenolepis diminuta and H. microstoma. Our results are the first to report anthelmintic efficacy of CPs against an economically important equine helminth. Moreover, they provide further evidence that the spectrum of activity of CPs is not restricted to nematodes and support the idea that these plant-derived enzymes can be developed into useful broad-spectrum anthelmintics.

Equine cestodosis: a sero-epidemiological study of Anoplocephala perfoliata infection in Ethiopia

A 12/13 kDa antigen, tapeworm ELISA test, developed for use in horses, was used to detect parasite-specific serum antibody, IgG(T), in the serum of donkeys. In a pilot study the 12/13 kDa antigen was tested and proved to detect the antibody, IgG(T), in donkey sera. Blood samples from 797 donkeys, naturally exposed to cestode infection, from four geographical localities were collected and sera were prepared and analysed. There was substantial serological evidence that donkeys were potentially infected with A. perfoliata. A range of ELISA OD values were obtained from the serological assay. Over 26% and 7.5% of the donkeys were moderately and highly infected, respectively, showing at least a 34% sero-prevalence. The rest, 66.1%, were either with low infection intensity or negative for A. perfoliata infection. The risk of infections, both in sero-prevalence and intensity, as determined by ELISA optical density (OD), were highest in the highland areas of Ethiopia where pastures are low-lying and wet, and permanent pasture management is regularly practised. Sex, age and body condition of the donkeys had no significant effect either on prevalence of the infection or on the serum antibody level. These results indicate a risk of intestinal disorders, particularly, colic, associated with A. perfoliata infection in donkeys.

Epidemiological studies on equine cestodes in central Spain: Infection pattern and population dynamics

An epidemiological study on equine cestodosis was carried out in central Spain. A total of 372 digestive tracts from equids slaughtered in abattoirs located in central Spain were studied from November 2001 to May 2004. Anoplocephala perfoliata was detected in 24% of the animals and Anoplocephala magna in 18%. Individual tapeworm burden was from 1 to 491 tapeworms for A. perfoliata and from 1 to 64 tapeworms for A. magna. Low tapeworm burdens (less than 30 cestodes) predominated significantly (p<0.01) in all seasons for both species. Seasonal prevalence of infection by A. perfoliata was significantly higher (p<0.01) in autumn (37.5%) and winter (32.3%) than in spring (9.2%) and summer (10.8%). Immature tapeworms were detected throughout summer (11%), autumn (23.4%) and winter (26.6%), signalling a summer to winter risk period for tapeworm infection in our conditions. Mature non-gravid tapeworms were collected in all seasons, with a decreasing pattern from summer (89%) to spring (6.7%). Conversely, gravid tapeworms showed an increasing pattern, from 0 in summer to a maximum (93.3%) in spring. Since prevalence of infection was significantly higher in winter than in spring, winter seems to be the season when more eggs would be available to be eaten by mites. A. perfoliata infection was detected in three different periods throughout the 3 year study: autumn 2001-winter 2002, summer 2002-spring 2003 and autumn 2003-spring 2004. This epidemiological pattern seems to describe the dependence of A. perfoliata to humidity in warm dry climate. In our conditions, A. perfoliata appears to follow a pattern of having only one generation per year, with a marked dependence on humidity. According to the results, autumn rainfall would influence the length, and late spring rainfall the appearance, of each annual generation. A. magna showed a different pattern. Infection was detected throughout the whole study period. Seasonal prevalence was higher in autumn (25.5%) than in winter (14.9%), spring (12.1%) and summer (10.5%), but the differences were not statistically significant. Non-gravid A. magna tapeworms could be detected almost throughout the year but percentages were significantly higher (p<0.01) in autumn (50.2%), indicating recent ingestion, than in the other seasons (30% in summer, 12.8% in winter and 0% in spring). However, data from spring were not enough to discard the season as a risk period for A. magna infection.

Anoplocephala perfoliataof horses – significant scope for further research, improved diagnosis and control

Anoplocephala perfoliatais the commonest tapeworm parasite of horses and is incriminated as a significant cause of clinical disease (e.g., ileocaecal intussusception, caeco-caecal intussusception and/or caecal perforation), particularly in horses chronically infected with large numbers of worms. The high prevalence (~20–80%) of the parasite in some countries suggests an increased risk of clinical cases. In spite of research, there is still a paucity of information regarding the pathogenesis of the disease, the epidemiology of the parasite in different geographical regions and there are significant limitations with the diagnosis of infection. The present article provides an account of the biology, epidemiology and pathogenic effects ofA. perfoliata, the diagnosis of infection and treatment. It highlights some gaps in knowledge of the parasite and the disease it causes, and suggests opportunities for future research and prospects for improved diagnosis, prevention and control.

Effects of oral administration of tilmicosin on pulmonary inflammation in piglets experimentally infected with Actinobacillus pleuropneumoniae

OBJECTIVES

To determine the effects of oral administration of tilmicosin in piglets experimentally infected with Actinobacillus pleuropneumoniae.

ANIMALS

Forty 3-week-old specific-pathogen free piglets.

PROCEDURES

Piglets were assigned to 1 of 4 groups as follows: 1) uninfected sham-treated control piglets; 2) infected untreated piglets that were intratracheally inoculated with 10(7) CFUs of A pleuropneumoniae; 3) infected treated piglets that were intratracheally inoculated with A pleuropneumoniae and received tilmicosin in feed (400 ppm [microg/g]) for 7 days prior to inoculation; or 4) infected treated piglets that were intratracheally inoculated with A pleuropneumoniae and received chlortetracycline (CTC) in feed (1100 ppm [microg/gl) for 7 days prior to inoculation. Bronchoalveolar lavage (BAL) fluid and lung tissue specimens of piglets for each group were evaluated at 3 or 24 hours after inoculation. For each time point, 4 to 6 piglets/group were studied.

RESULTS

Feeding of CTC and tilmicosin decreased bacterial load in lungs of infected piglets. Tilmicosin delivered in feed, but not CTC, enhanced apoptosis in porcine BAL fluid leukocytes. This was associated with a decrease in LTB4 concentrations in BAL fluid of tilmicosin-treated piglets, compared with untreated and CTC-treated piglets, and also with a significant decrease in the number of pulmonary lesions. Tilmicosin inhibited infection-induced increases in rectal temperatures, as measured in untreated and CTC-treated piglets. Pulmonary neutrophil infiltration and prostaglandin E2 concentrations in the BAL fluid were not significantly different among groups at any time.

CONCLUSIONS AND CLINICAL RELEVANCE

Oral administration of tilmicosin to infected piglets induces apoptosis in BAL fluid leukocytes and decreases BAL fluid LTB4 concentrations and inflammatory lung lesions.

Tissue pharmacokinetics of florfenicol in pigs experimentally infected with Actinobacillus pleuropneumoniae

The aim of this study has been to determine the tissue pharmacokinetic parameters of florfenicol in the pigs experimentally infected with Actinobacillus pleuropneumoniae. 21 crossed-bred (Duroc x Landrace x Yorkshire) local species of pigs were infected experimentally with Actinobacillus pleuropneumoniae serotype 1 and confirmed as typical sub-acute pleuropneumonia. A single dose of 20 mg/kg body weight of florfenicol, a novel animal-using antibiotic, was administrated intramuscularly in the pigs and then samples of blood, lung, trachea with bronchi, liver, kidney and muscle were taken at scheduled time points. Drug concentrations were determined by high performance liquid chromatography (HPLC) with an ultraviolet detector via extraction with ethyl acetate under nitrogen flow. The statistic moment theory (SMT) mathematic package was applied to calculate the tissue pharmacokinetic parameters of florfenicol in the infected model. AUC of lung, trachea with bronchi, liver, kidney and muscle were 121.69, 79.37, 81.05, 181.2, and 94.07 mg/l x h, respectively, MRT were from 34.66 to 90.17 h, and t1/2beta from 24.75 to 69.34 h, respectively.

CONCLUSIONS

Florfenicol was widely distributed in these tissues and maintained the effective therapeutic concentrations especially in the respiratory tract tissues that are the target organs of Actinobacillus pneuropneumoniae.

CLINICAL SIGNIFICANCE

Tissue pharmacokinetic data could be evidence for regime designing of florfenicol in treatment of porcine pleuropneumonia.

A comparative study of the preventive use of tilmicosin phosphate (Pulmotil premix) and Mycoplasma hyopneumoniae vaccination in a pig herd with chronic respiratory disease

This study was conducted to compare the effects of a preventive in-feed medication programme using tilmicosin (Pulmotil 200 premix, Elanco Animal Health) at 200 p.p.m. with those of Mycoplasma hyopneumoniae (Mh) vaccination programme (Stellamune Mycoplasma, Pfizer Animal Health). A pig herd with chronic respiratory disease in which infection with Mh played an important role was selected, and a total of 204 piglets were randomly allocated to either the medication (P) or the vaccination (V) group. Pigs in the P group received medicated feed for 3 weeks after weaning (days 34-55), and for 2 weeks late in the nursery period (days 77-98). The piglets in the V group were vaccinated twice intramuscularly, at 4 and 22 days of age. The two groups were compared on the basis of average daily gain (ADG), feed conversion rate (FCR), additional curative medication days (CMD), overall mortality (major variables), a coughing index, pneumonia lesions, and serology against Mh, influenza H1N1 and influenza H3N2 viruses, Actinobacillus pleuropneumoniae (App) and porcine reproductive and respirator, syndrome virus (PRRSV) (minor variables). No significant differences (P > 0.05) were observed for ADG (555 g/day in P group; 567 g/day in V group), FCR (2.64 in P group; 2.41 in V group) and mortality rate (11% in P group; 7% in V group). The average number of additional curative medication days (CMD) per pig was significantly higher (P < 0.01) in the P group (1.5) than in the V group (0.58). At slaughter age, the serological results and the prevalence of macroscopic lung lesions were comparable in the two groups (P > 0.05). With the exception of CMD, the preventive use of tilmicosin at this swine farm was found to confer similar beneficial effects to Mh vaccination.

Effect of enrofloxacin-Na against pathogens related to the respiratory and alimentary diseases in suckling and weanling piglets

A field trial was conducted to evaluate effect of enrofloxacin-Na against pathogens related to the respiratory and alimentary diseases in eighty suckling piglets (6-7 days old) and eighty weanling piglets (5-6 weeks old). Respective twenty of the suckling and weanling piglets were assigned to each of 4 experimental groups; control (non-treated), clinical injection dose (CID), 2x clinical injection dose (2CID). and premix. A 0.05 ml (2.5 mg) of enrofloxacin-Na injection (5% solution, 1 ml) per kg body weight of piglets as CID was injected intramuscularly for 3 days and the clinical signs were observed for 9 days. The premix (150 ppm) of enrofloxacin-Na was administered with feed for 7 days ad libitum and the clinical signs were observed for 13 days. The enrofloxacin-Na-treated piglets showed a higher increase in body weight and a lower feed per gain than the control piglets. In addition, the treatment of enrofloxacin-Na, regardless of the route of administration, decreased the incidence rate of diarrhea in suckling piglets and respiratory symptoms in weanling piglets. The isolation index of E. coli and Cl. perfringens during the treatment periods was also lowered by the enrofloxacin-Na treatment in both suckling and weanling piglets. The antibiotics was also evaluated as safe locally and whole bodily as treated by injection or feeding. These results indicate that the newly developed antibiotics, enrofloxacin-Na, is very useful for the prevention and therapy of swine diseases in the pig industry.

Relationship between the amounts of antibodies to Actinobacillus pleuropneumoniae serotype 2 detected in blood serum and in fluids collected from muscles of pigs

An indirect ELISA method, previously used to detect antibodies to Actinobacillus pleuropneumoniae serotype 2 in serum of pigs, was further developed aiming to measure antibodies to the microbe in muscle fluids. Serum and muscle fluid were collected from Specific Pathogen Free (SPF) pigs as well as from SPF pigs challenged with A. pleuropneumoniae which were either treated with effective antibiotics or left as infected controls. The antibody responses measured in serum correlated well to the clinical signs of respiratory disease observed and to pathological lesions found at necropsy performed 17 days post-infection. The amounts of antibodies monitored in serum and in muscle fluid collected from the diaphragm and the thigh, respectively, were compared. Higher concentrations of antibodies were assessed in serum than in diaphragm fluid, which in turn contained more antibodies per ml than fluid collected from the thigh. The amount of antibodies to A. pleuropneumoniae measured in fluid from the diaphragm diluted 1/50 correlated well with the quantity measured in serum diluted 1/1000 (r2 = 0.87; P < 0.001). When validated by using serum antibody responses as a standard, the specificity of the ELISA employed in fluid from the diaphragm was found to be 100%. The sensitivity was determined to be 88% when calculated on seropositive pigs (A450 = 0.3 in serum diluted 1/1000). That figure increased to 97% if calculated on pigs expressing pronounced amounts of serum antibodies (A450 > or = 0.5).