Worm Counts Research Articles

Assessment of Echinacea purpurea and mefloquine in treatment of Schistosoma mansoni

Objective To assess the effect of combined Echinacea purpurea (EP) and mefloquine (MQ) in the treatment of experimental Schistosoma mansoni infection. Background Schistosomiasis is a prevalent parasitic disease in tropical and subtropical areas caused by the flatworm S. mansoni. Several medications are used in the treatment of schistosomiasis. Praziquantel (PZQ) is the drug of choice because of its safety and broad-spectrum activity. Materials and methods The current study was carried out on 120 laboratory-bred Swiss albino female mice. They were classified into six groups: group I (control), group II (PZQ treated), group III (MQ treated), group IV (EP treated), group V (PZQ and EP), and group VI (MQ and EP). Evaluation was done parasitologically using the worm count technique, ova count technique in intestine and liver, and oogram pattern and histopathological examination of liver sections for assessment of granuloma size and diameter. Moreover, electron microscopic changes of the adult worms were evaluated. Results The highest worm burden reduction of male (79.41%), female (82.28%), couples (86.6%), and total (92%) worms was obtained in the combined MQ and EP treated group. The highest reduction in the mean number of ova count/g tissue in either the intestine (93%) or the liver (89%) was detected in MQ and EP treated group. In combined treated groups, the highest percentage of reduction in the immature and mature eggs was detected in the group MQ and EP; it was 9.16 ± 4.11 and 5.25 ± 2.56, respectively. Moreover, there was an increase in the percentage of dead eggs (85.58 ± 6.43). The highest reductions in hepatic granuloma diameter and number were seen in the combination of MQ and EP at 67 and 85%, respectively (P Conclusion MQ has effective schistosomicidal properties through reduction of worm burden and tissue egg load. Moreover, EP extract showed promising antischistosomal activity on S. mansoni-infected mice. It is recommended to study the exact mechanism of action of EP on S. mansoni and its possible effects on other parasitic infections.

Efficacy of 10% imidacloprid +\xa02.5% moxidectin topical solution (Advantage Multi\xae for Dogs) for the prevention of heartworm disease and infection all month long

BackgroundPrior work has shown that the levels of moxidectin in dogs treated with Advantage Multi® for Dogs (Bayer Animal Health) remain at a high plasma concentration for the full month after application. The objective of this study was to demonstrate the efficacy of 10% imidacloprid + 2.5% moxidectin topical solution (Advantage Multi® for Dogs, also known as Advocate® for Dogs) for the prevention of heartworm infection and disease 30 days after just one application.MethodsTwo groups of eight dogs each were included. Dogs in Group 1 received the product (Advantage Multi® for Dogs) while those in Group 2 remained as nontreated controls. All dogs entering the study completed a physical examination including examination for Dirofilaria immitis antigen and circulating microfilariae. Dogs in Group 1 were treated on Study Day (SD) –30 as per the label recommendation. Thirty days later (SD 0) dogs in Groups 1 and 2 were subcutaneously infected in the inguinal region with approximately 50 infective third-stage D. immitis larvae (“Missouri” isolate). Blood was collected on SDs 120 and 147 for examination for D. immitis antigen and circulating microfilariae. On SD 148, all animals were euthanized and necropsied for recovery of adult heartworms. All procedures were performed in accordance with the VICH GL9 guidelines.ResultsExamination and worm counts made at necropsy showed no heartworms in the treated dogs (Group 1) compared with six of eight nontreated dogs (Group 2) with heartworms (range of 2–33). The treated dogs (Group 1) had significantly fewer heartworms (p < 0.05) compared with the nontreated controls (Group 2).ConclusionThe results demonstrated that 10% imidacloprid + 2.5% moxidectin topical solution (Advantage Multi® for Dogs) is efficacious for the prevention of heartworm infection and disease all month long with no observation of treatment-related adverse events.

Prevalence of gastrointestinal helminth infections in free-range laying hens under mountain farming production conditions

ABSTRACT1. A cross-sectional study was conducted from September 2015 to July 2016 in South Tyrol, Northern Italy to examine the prevalence of gastrointestinal helminths in free-range laying hens under mountain farming production conditions.2. A total of 280 laying hens from 14 free-range mountain farms (4 organic, 10 conventional) were randomly collected at the end of the laying period. Faecal samples were taken to analyse faecal egg counts (FEC) and faecal oocyst counts (FOC). The gastrointestinal tracts were removed post mortem and examined for the presence of helminths.3. In faeces, FEC values averaged 258 eggs per g of faeces, which were dominated by Ascaridia galli and Heterakis gallinarum. Mean FOC was 80 oocysts/g. In the gastrointestinal tract, at least one nematode species was found in 99.3% of the examined hens. H. gallinarum was the most prevalent nematode (95.7%), followed by Capillaria spp. (66.8%) and A. galli (63.6%). Thirty per cent of the chickens were infected with cestodes (tapeworms). Correlation coefficients between worm counts of H. gallinarum, Capillaria spp. and A. galli ranged from 0.41 to 0.51.5. The helminth prevalence did not differ between conventional and organic farms, whereas total worm burden was higher in organic compared with conventional farms (318.9 vs. 112.0). Prevalence and infection intensity did not differ between farms that used anthelmintic treatments and those that did not.6. In conclusion, free-range laying hens under the studied mountain farming conditions are at high risk of nematode infection, especially in organic systems. The vast majority of hens are subclinical infected with at least one helminth species.

Strongyloides westeri worm and egg counts in naturally infected young horses

Strongyloides westeri is a threadworm parasite found in the small intestine mainly in foals at up to about 4 months of age. This parasite is associated with small intestinal enteritis and diarrhea as well as skin irritation and a clinical syndrome called “frenzied behavior” due to percutaneous invasion. The aim of this study was to investigate S. westeri parasite burdens in age groups older than the initial lactogenic transmission phase. Secondary aims were to examine the impact of host age and gender on worm burden and egg output in naturally infected foals. Thirteen foals were enrolled in the study, exposed to natural infection with S. westeri and were humanely euthanized at ages ranging from 89 to 221days old. Egg counts per gram of feces were determined using the Mini-FLOTAC method. Worms were retrieved from the mucosa of the anterior half of the small intestine using a digestion method and enumerated. The foals were all observed to be healthy with no signs of parasitic disease. Foals at 4–5 months of age had significantly higher S. westeri worm and egg counts compared to those aged 6–8 months (p<0.05). Fecal egg counts were significantly associated with worm counts (p=0.0045). While egg and worm counts declined markedly in the 6–8 month age range, they were not eliminated completely. This could either reflect a new infection acquired orally or transcutaneously, or a subset of adult intestinal parasites acquired via the lactogenic route and surviving for longer time periods. This study provided new information about S. westeri infection patterns in young horses at 4–8 months of age.

Anthelmintic therapy of equine cyathostomin nematodes – larvicidal efficacy, egg reappearance period, and drug resistance

Cyathostomins are ubiquitous in grazing horses across the world, and anthelmintic resistance has been reported with increasing levels over past decades. The aims of the present study were (i) to investigate the efficacy against encysted larval stages of moxidectin (0.4 mg/kg) and fenbendazole (10 mg/kg daily for five consecutive days) and compare these regimens at 2 and 5 weeks post-treatment, (ii) to investigate individual cyathostomin species associated with shortened egg reappearance periods, and (iii) to document species exhibiting decreased susceptibility to the evaluated compounds. Thirty-six ponies were allocated to treatment groups with half euthanatized 2 weeks post-treatment, and the remainder necropsied after 5 weeks. Luminal and mucosal worm counts were conducted and strongyle egg counts were determined at weekly intervals. At 2 weeks, mean reductions of early L3s were 50.4% and 73.8% for fenbendazole and moxidectin, respectively. At 5 weeks, the respective efficacies were 51.3% and 71.8%. Two week efficacies against late L3s and L4s (LL3s/L4s) were 70.8% and 74.6% for fenbendazole and moxidectin, respectively, whereas very low numbers were found in all three groups at 5 weeks. None of the mucosal counts were significantly different between treatment groups. Fenbendazole and moxidectin reduced luminal worm counts by 93.2% and 98.3% at 2 weeks following administration, with moxidectin group adult counts being significantly lower than the other two groups (P < 0.0001). Both treatment groups had increased counts 3 weeks later (P = 0.0415). A moxidectin ERP of 4 weeks was associated with surviving luminal L4s, and adult species contributing to this were Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicocyclus ashworthi and Cylicocyclus nassatus. This study documented (i) larvicidal efficacy of fenbendazole much lower than historical standards, (ii) survival of luminal immatures (L4) following moxidectin administration, and (iii) new information about cyathostomin species associated with these phenomena.

In vitro and in vivo anthelmintic efficacy of two pentacyclic triterpenoids, ursolic acid and betulinic acid against mice pinworm, Syphacia obvelata.

Pinworm infections are one of the common problems in laboratory rodents and man. At present there are only few drugs against intestinal helminths, and new drugs are urgently needed to cope up any future risk of drug resistance. Interest in plant secondary metabolites (PSMs) has risen considerably in the recent years for the discovery and development of new drugs. In the present study, we explored the in vitro and in vivo anthelmintic potentials of two pentacyclic triterpenoids, ursolic acid (UA) and betulinic acid (BA), the important PSMs of many medicinal plants, against Syphacia obvelata (Nematoda: Oxyuridae), a common pinworm of mice. The results of this study indicated that in both, in vitro and in vivo assays, BA showed comparatively better anthelmintic effects than UA. In the in vitro assay, 1.00mg/ml concentration of BA showed paralysis and mortality of worms in 1.20±0.04 and 2.30±0.03h, respectively. In the in vivo assay, a single 10.00mg/kg dose of BA, administered for 5days, revealed 68.78% reduction in egg counts and 84.08% reduction in worm counts of infected mice. The present study suggests that BA holds a great promise to be pursued further for detailed testing against some other representative group of helminth parasites.

Response of Nigerian local breed of dog to graded doses of &lt;i&gt;Ancylostoma caninum&lt;/i&gt; infection

The experiment investigated the response of Nigerian local breed of dog to different doses of Ancylostoma caninum infection. Sixteen dogs aged 6 to 7 months and assigned to 4 groups (A – D) of 4 dogs each were used. Groups A, B and C were infected with 100, 200 and 400 A. caninum infective larvae (L 3 ) while group D served as the uninfected control. Faecal egg count (FEC), red blood cell (RBC) counts, haemoglobin concentrations (HBC), packed cell volume (PCV) and body weight (BWT) were evaluated weekly from day 0 (D0) to D56 post-infection (Pi). The dogs were humanely sacrificed on D56 Pi to determine the adult worm count (WC). The mean FEC of dogs given 400 L 3 (group C) was significantly (P 0.05) difference between the mean FEC of groups B (200 L 3 ) and C dogs. The group C dogs had significantly higher (P ≤ 0.05) worm burden than those in groups B and A. There was a dose dependent reduction in RBC counts, HBC and PCV of the infected dogs which was most significant (P < 0.05) in group C followed by group B. The control and group A dogs had a BWT gains of 0.75 and 0.15 kg, respectively at the end of the experiment when compared to their D0 BWT while groups B and C lost 1.70 and 3.30 Kg of their BWT by D56 respectively. The results of this study showed that while the FEC did not differ significantly among the infected dogs, other measures of parasite intensity, namely, WC, PCV, RBC, HBC and BWT differed in a dose dependent manner. Keywords: Ancylostoma caninum , Dogs, infective dose, Nigeria, Response

Between-breed variations in resistance/resilience to gastrointestinal nematodes among indigenous goat breeds in Uganda

Gastrointestinal nematodes (GINs), Haemonchus contortus, are a major health problem in goat production. Resistance to H. contortus, the most prevalent GIN in Uganda, was studied among three indigenous goat breeds to assess their differences. Twelve male goats of each breed approximately 7 months old of small East African (SEA), Mubende, and Kigezi goats from smallholder farmers in Arua, Mubende, and Kabale were assembled for the study. At the station, they were dewormed with a combination therapy of the broad-spectrum dewormers closantel and albendazole to free the goats of gastrointestinal parasites. During experimentation, the goats were kept indoors and ad libitum fed on clean banana peels and napier grass. On attainment of zero-worm-egg status, the goats were artificially infected with 18,000 third-stage (L3) larvae of H. contortus prepared according to Baermann’s procedure. Data were collected on fecal egg count (FEC), packed cell volume (PCV), and body weight (BW) on a 2-week basis until 12 weeks post infection and carcass weight and total worm count (WC) in the abomasum at termination of the experiment. The data on FEC, PCV, and BW were subjected to repeated-measure analysis of variance and the others by one-way analysis of variance. FEC between breeds was only significantly different at 12 weeks post infection (p = 0.04). Generally, higher FEC was recorded in Kigezi compared to SEA and Mubende goats. Carcass weight was significantly different among breeds (p < 0.05), with Mubende having the highest carcass weight, followed by Kigezi and SEA. PCV and daily weight gains were significantly different between breeds (p < 0.05). WC was not significantly different between the breeds. FEC and PCV were weakly significant at later stages of the experiment with higher parasite burden suggesting potential variation in resistance to H. contortus. These differences could be exploited in designing breeding programs with disease resistance in indigenous goat breeds.

An attempt to replace an ivermectin-resistant Cooperia spp. population by a susceptible one on grazing pastures based on epidemiological principles and refugia management

The maintenance of anthelmintic-susceptible parasite refugia to delay the onset of anthelmintic resistance is an almost impossible effort in many grazing livestock production countries given that current refugia consist of already resistant parasites. Rather, efforts could be focused on replacing the resistant parasite refugia by susceptible parasite ones and implementing sustainable parasite control measures from then on. To this purpose, a trial was conducted to attempt to establish a new population of ivermectin-susceptible Cooperia sp. on a beef cattle farm with proven problems of ivermectin-resistant Cooperia. During two consecutive years, 82 (Year 1) and 100 (Year 2) recently weaned and parasite-free heifers were inoculated with 40,000 or 30,000 susceptible Cooperia L3, respectively, at a time when levels of resistant parasite refugia were normally low. The animals were subsequently allowed to graze on the problem pastures during autumn until the end of spring. Levels of parasitism in the animals and on pasture were monitored monthly and animals were treated with levamisole when needed. The combination of parasitological monitoring and local epidemiological knowledge was essential to determine when treatments were to be administered. No clinical signs of gastrointestinal parasitosis in the herd were observed throughout the study and unnecessary treatments were avoided. Faecal egg counts reduction tests (FECRT) and controlled efficacy tests (CET) employing worm counts were carried out at different times throughout the study to determine the clinical efficacy (FECRT) and the absolute efficacy (CET) of ivermectin, respectively. The clinical efficacy of ivermectin increased from an initial 73% to 99.4%, while the absolute efficacy increased from 54.1% to 87.5% after just two animal production cycles. The switch from a resistant parasite population to a susceptible one requires knowledge of parasitological epidemiology, especially in relation to seasonal variations of parasite populations in both the host and in refugia.

A comparative study on the anti-schistosomal and hepatoprotective effects of vinpocetine and isosorbide-5-mononitrate on Schistosoma mansoni-infected mice

Schistosomiasis is a remarkable public health problem in developing countries. Presently, praziquantel is the optional drug for all human schistosomiasis. Owing to the increased praziquantel resistance, there is an urgent need to develop new alternatives. This study aims at determining the anti-schistosomal and/or the hepatoprotective effects of the anti-inflammatory drug; vinpocetine, and the vasodilator and the nitric oxide donor; isosorbide-5-mononitrate, in comparison to praziquantel. In the present research, the therapeutic efficacies of these drugs were assessed in Swiss albino female mice (CD-I strain) experimentally infected with an Egyptian strain of Schistosoma mansoni, using some general, parasitological, and histopathological parameters. In this work, praziquantel significantly reduced worm burden and hepatic egg load, increased the percentage of dead eggs in the small intestine and decreased granuloma count, but did not reduce granuloma diameter. While, either vinpocetine or isosorbide-5-mononitrate monotherapy did not induce significant reduction in the worm count, hepatic egg load or shift in the oogram pattern, but significantly reduced granuloma count and diameter. Moreover, isosorbide-5-mononitrate significantly reduced hepatic inflammation and necrosis. The best results were obtained in the mice groups treated with isosorbide-5-mononitrate combined with praziquantel or vinpocetine. Our results point to vinpocetine and isosorbide-5-mononitrate as a convenient and promising adjuvant to praziquantel for ameliorating schistosomal liver pathology. Further studies are recommended to reveal the actual pathways responsible for the different activities of vinpocetine and isosorbide-5-mononitrate.

Immunoprotective Effect of Chitosan Particles on Hymenolepis nana - Infected Mice.

Hymenolepis nana is the most commonly known intestinal cestode infecting mainly human. This study aimed to investigate the potential effect of chitosan particles (CSP) to enhance the immune system against H.nana infection. Determination of worm burden, egg output, histopathological changes, oxidative stress markers (lipid peroxidation and reduced glutathione), goblet (GCs) and mucosal mast cells (MMCs) counts in intestinal ileum was performed. In addition, levels of intestinal mRNA expression of interleukin (IL)-4, IL-9, stem cell factor (SCF), type I and II interferons (IFN)-α/ γ, tumour necrosis factor (TNF)-α, mucin 2 (MUC2) and inducible nitric oxide synthase (iNOs) were investigated using real-time PCR. The results indicated induced reductions in adult worm and egg counts in infected mice after CSP treatment. This was associated with improvement in tissue morphometric measurements and oxidative stress which were altered after infection. Expression levels of iNOs, IFN-α, IFN-γ, TNF-α and IL-9 were decreased by CSP. Conversely, expression levels of MUC2, IL-4 and SCF increased compared to infected untreated group. In addition, GCs and MMCs counts were normalized by CSP. In conclusion, this study could indicate the immunoprotective effect of CSP against H.nana infection. This was characterized with Th2 anti-inflammatory responses.

Oral contraceptive pills: Risky or protective in case of Trichinella spiralis infection?

The aim of this study was to investigate how Trichinella spiralis infection can be affected by contraceptive pills in vivo. Methods included six groups of female Wistar rats; healthy, Trichinella infected, receiving combined contraceptive pills (COCPs), receiving progestin only pills (POPs), infected receiving COCPs and infected receiving POPs. Parasite burden was measured; adult worm counts, gravidity, larvae and reproductive capacity index). Histopathological examination, immunohistochemical detection of C-kit+ mast cells and Foxp3+ T-reg. cells in intestinal sections, eosinophils muscle infiltration and CPK level were performed. Rats infected and receiving COCPs showed a significant increase in parasitic burden, and infected receiving POPs showed a significant reduction compared to infected only, with a significant increase in nongravid females (Mean total worms=964.40±55.9, 742±52.63, 686±31.68, larvae/g=5030±198.75, 2490±143.18 and 4126±152,91, respectively). Intestinal sections from infected receiving COCPs showed intact mucosa (though the high inflammatory cells infiltrate), and significant increase in C-kit+ mast cells number and intensity (30.20±4.15 and 60.40±8.29), and Foxp3+ T-reg. cells (10±1.58). Infected receiving POPs showed a significantly less CPK (5886±574.40) and eosinophilic muscle infiltration (58±13.51). Oestrogen-containing pills established a favourable intestinal environment for Trichinella by enhancing Foxp+T-reg. cells and stabilizing C-kit+mast cells, while POPs gave a potential protection with less gravidity, larval burden and eosinophilic infiltrate.

Tropical plant supplementation effects on the performance and parasite burden of goats.

ObjectiveExamine the effects of supplementing bahiagrass hay (BG) with potentially anthelmintic quantities of hays of perennial peanut (PEA) or sericea lespedeza (LES) or seeds of velvet bean (Mucuna pruriens L.; MUC) or papaya (PAP) on the intake and nutritive value (Experiment 1), and the performance and parasite burden (Experiment 2) of goats.MethodsIn Experiment 1, 38 male goats (27.4±5.7 kg body weight) were randomly assigned to each of 5 treatments: i) BG alone and BG plus; ii) PEA; iii) LES; iv) MUC; and v) PAP. Goats were fed for ad libitum consumption and adapted to the diets for 14 d followed by 7 d of measurement. The PEA, LES, MUC (50%, 50%, and 10% of the diet dry matter [DM], respectively), and PAP (forced-fed at 10 g/d) were fed at rates that would elicit anthelmintic effects. In Experiment 2, goats remained in the same treatments but were allocated to 15 pens (3 pens per treatment) from d 22 to 63. All goats were infected with parasites by grazing an infected bahiagrass pasture from 0800 to 1500 h daily and then returned to the pens.ResultsDry matter intake tended to be greater in goats fed PEA and LES than those fed BG (757 and 745 vs 612 g/d, respectively). Digestibility of DM (59.5% vs 54.9%) and organic matter (60.8% vs 56.0%) were greater in goats fed MUC vs BG, respectively. In Experiment 2, feeding PAP, LES, and PEA to goats reduced nematode fecal egg counts by 72%, 52%, and 32%, reduced abomasal adult worm counts by 78%, 52%, and 42%, and decreased plasma haptoglobin concentrations by 42%, 40%, and 45% relative to feeding BG alone, respectively.ConclusionSupplementation with PEA, LES, and PAP decreased the parasite burden of goats but did not increase their performance. PAP was the most effective anthelmintic supplement.

Establishment rate of cattle gastrointestinal nematodes in farmed red deer (Cervus elaphus)

Red deer can be infected with some gastrointestinal nematodes (GIN) of cattle but it is unknown to what extent. An indoor study was conducted to determine the establishment rate of cattle GIN in young deer. Five young calves and 5 young red deer were used. They were effectively treated with anthelmintics when housed and then infected 2 weeks later. After four weeks they were killed for total worm counts. Establishment rates were assessed comparing worm counts to the infective dose which were identified morphologically, and to the relative establishment rate of different species. The establishment rates (%) in cattle and deer respectively were H. contortus (8.0, 18.7, p=0.18), Ostertagia ostertagi (30.8, 0.7, p<0.001), Cooperia spp. (72.3, 2.3, p<0.001) and Trichostrongylus spp. (19.0, 25.3, p=0.12). The majority (>98%) of Trichostrongylus spp. were Trichostrongylus axei in both hosts and there were no differences between hosts for this species (p=0.11). In cattle >98% of Cooperia were Cooperia oncophora and the mean burden was much higher than in deer (p<0.01) where there were similar proportions of Cooperia oncophora, Cooperia punctata and C. curticei. Small numbers of Oesophagostomum venulosum were also present with 3X as many found in deer as in cattle (p<0.05). This study has shown that some cattle-origin GIN can establish in red deer. In particular, the establishment of H. contortus and T. axei could allow sufficient burdens to build up to be clinically significant. Importantly, almost no cattle Ostertagia species or small intestinal species established in deer.

Modulation of murine intestinal immunity by Moringa oleifera extract in experimental hymenolepiasis nana.

The potential therapeutic value of Moringa oleifera extract (MOE), due to its anti-inflammatory and anti-oxidant effects, has been reported previously. In this study, Hymenolepis nana antigen (HNA) in combination with MOE was used in immunization against H. nana infection. Adult worm and egg counts were taken, while histological changes in the intestine were observed. Mucosal mast (MMCs) and goblet cells (GCs) were stained with specific stains, while serum and intestinal IgA were assayed using enzyme-linked immunosorbent assay (ELISA). Reduced glutathione (GSH) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS) were assayed. Real-time polymerase chain reaction (PCR) was used for detection of mRNA expression in ileum tissue. The results demonstrated an improvement in the architecture of intestinal villi, decreased inducible nitric oxide synthase (iNOs) and TBARS, and increased GSH in HNA, MOE and MOE + HNA groups. In the same groups, an increase in GCs, mucin 2 (MUC2), interleukins (IL)-4, -5 and -9, and stem cell factor (SCF) versus a decrease in both interferon-gamma (IFN-γ) and transforming growth factor (TGF-β) expression appeared. HNA and MOE + HNA increased serum and intestinal IgA, respectively. MOE decreased MMCs and achieved the highest reductions in both adult worms and eggs. In conclusion, MOE could achieve protection against H. nana infections through decreased TGF-β, IFN-γ and MMC counts versus increased GC counts, T-helper cell type 2 (Th2) cytokines and IgA level.

Efficacy of a new spot-on formulation of selamectin plus sarolaner against Ancylostoma tubaeforme and Toxocara cati in cats

The efficacy of a new spot-on formulation of selamectin plus sarolaner for cats was evaluated against induced infections with Ancylostoma tubaeforme (hookworm) and Toxocara cati (roundworm). Five laboratory studies were conducted using adult, purpose-bred cats. Four of the studies were designed to evaluate efficacy of the combination against A. tubaeforme, the dose-limiting gastrointestinal nematode species for selamectin. In two of these studies non-interference between selamectin and sarolaner was also evaluated. The fifth study evaluated efficacy of the combination against mixed infections of A. tubaeforme and T. cati. The hookworm isolates in three studies were of US origin, as was the roundworm isolate. In the two remaining studies, cats were inoculated with a hookworm isolate of European origin. Cats were inoculated with 150 (±50) to 200 (±50) infective hookworm larvae 30–42days prior to treatment and with 400 infective roundworm eggs 60days prior to treatment. Cats were ranked by pre-treatment faecal egg counts and randomly allocated to different treatment groups. In all studies, cats were treated at the minimum label dose to provide 6.0mg selamectin per kg bodyweight. All animals were euthanized 7–10days after treatment for worm counts. Efficacy was calculated based on the reduction of the geometric mean worm counts in the treated groups versus the placebo-treated control groups.The efficacy against adult hookworms was 99.2%, 94.3% and 100% in three of these studies, and was lower in the remaining two studies. The efficacy against T. cati was 100%. Furthermore, non-interference between sarolaner and selamectin was demonstrated. Thus, a single topical application of the new spot-on formulation of selamectin plus sarolaner at the minimum label dose is effective in the treatment of adult hookworm and roundworm infections in cats.

Interaction between &lt;i&gt;Trypanosoma brucei&lt;/i&gt; and &lt;i&gt;Haemonchus contortus&lt;/i&gt; infection in West African Dwarf Goats

In order to investigate the immunomodulatory influence of concurrent T. brucei and H. contortus infection in West African Dwarf (WAD) goats, 28 infected and 7 uninfected (control) of 8-9 months old male WAD goats were studied. The infected goats were separated into resistant (Class 1) and susceptible (Class 2) Faecal Eggs Count (FEC) phenotypes. They were infected with 3000 infective larvae (L3) of H. contortus and 5 x 10 6 T. brucei . Another group of these phenotypes received only the H. contortus challenge. The responses were measured by parasitological response through FEC and Worm Burden (WB), and by host immune response through IgG levels. Class 2 animals with or without T. brucei infection exhibited non-significant (P > 0.05) higher FEC compared to those of Class 1. Worm burdens were not significantly different between FEC classes but were different (P=0.038) in relation to T. brucei infection. There was an overall increase in worm burdens of T. brucei infected goats, more pronounced in Class 2 than in Class 1. There was a significant upward drift of antibody levels with time across all groups without significant interactions. However, there was a significant effect of FEC Class (P=0.017) and trypanosome infection (P=0.041) with no significant interaction. Animals in Class 1 had generally higher antibody levels than those in Class 2, irrespective of T. brucei infection. Infection status had a highly significant (P=0.0001) effect on IgG. H. contortus only infected goats had the highest antibody levels and trypanosome infection reduced this response, irrespective of FEC phenotype. There was a highly significant (P=0.001) positive correlation (r = +0.719) between FEC and total worm counts. This work showed that the two response phenotypes identified in earlier immunizing infections were still clearly recognizable following homologous challenge and dual infections. This suggests that under field conditions where repeated H. contortus challenge occurs and trypanosomosis is endemic, the phenotypes could remain unchanged. © 2016 International Formulae Group. All rights reserved. Keywords: Haemoparasite, Gastrointestinal parasite, concurrent infection, immune response, domestic animals

Moderate and high levels of dietary protein on clinico-biochemical and production responses of lambs to repeated Haemonchus contortus infection

Effect of moderate and high levels of dietary protein and repeated Haemonchus contortus infection on clinical-biochemical and production responses was studied in Chokla lambs. In a 2×2 factorial design, two levels of protein (moderate, MP and high, HP) was supplemented to control (C) and infected (I; challenged with H. contortus) lambs. Thus, twenty-four 4 to 5 months old Chokla lambs (16.8±0.53kg) were randomly distributed into a total of 4 treatment groups of 6 animals each, designated as MPC (moderate protein control), MPI (moderate protein infected), HPC (high protein control) and HPI (high protein infected). The infected groups were drenched with 300 infective larvae (L3)/kg LW on day 0 and subsequently with 400 L3/kg LW three times a week for 10 consecutive weeks. Concentrate was restricted to 2.5% of live weight (LW) and roughage was offered ad libitum. Weekly record of body weight and faecal egg counts (FEC) and bi-weekly assessment of haematological parameters such as haemoglobin, packed cell volume, differential leucocyte count and biochemical parameters such as serum protein, albumin, iron, urea, creatinine and cholesterol were followed during the experimental period of 10 weeks. A metabolism trial was conducted after 8 weeks of experimental feeding to assess N utilization pattern in different groups. Lambs in HP had higher feed and nutrient intake (DM, CP, OM, ME) than MP. Infection exerted a more significant adverse effect on feed and nutrient intake by lambs in MP. Lambs of MPI showed a lower N balance corresponding with a lower N uptake, but had similar utilization efficiency. They also had lower (P<0.05) average daily gain, but no significant effect on body condition score. No clinical signs were evident in infected lambs on varied protein nutrition. Although FEC and adult worm counts were higher in MPI, a varied FEC peak during 4 and 5 weeks in HP and MP, respectively was indicative of non-significant effect of increasing protein nutrition on parasite establishment. However, there was significant improvement in the ability of lambs to withstand the pathogenic effects of H. contortus infection in HPI suggesting that the diet associated with increased resilience. A decreased performance in MPI could be overcome by increasing diet palatability that ensures adequate uptake of protein.

Can Haemonchus placei-primary infected naïve lambs withstand Haemonchus contortus infections?

An experiment was conducted with the objective of evaluating whether a 5000 L3 larvae Haemonchus placei primary infection, a less pathogenic parasite species for sheep, could attenuate highly pathogenic Haemonchus contortus infections in lambs. Thirty nine 6-month-old lambs were divided in three primary-infection groups: (HcPI) H. contortus-primary infected lambs, (HpPI) H. placei-primary infected lambs, and (CTRL) non-infected control lambs. Later, these same individuals, then aged 10-month old, were cross challenged with Haemonchus parasite species, creating four groups: HcPI challenged with H. placei (HcPI-HpCH), HpPI challenged with H. contortus (HpPI-HcCH), HcPI challenged with H. contortus (HcPI-HcCH), and CTRL. After a 60-day challenge period, all animals were necropsied for gastrointestinal worm counts. HcPI faecal egg count average was found to be twice the HpPI FEC group (p<0.0001). The HcPI also showed lower packed cell volume averages compared to the other groups (p<0.0001). Both H. contortus- and H. placei-primary infections displayed immune responses with similar IgG levels. For the challenge trial, the larval doses used were not enough to trigger clinic infection signs in all treated groups, compared to controls, and H. placei primary infection was not able to maintain anti-H. contortus IgG levels in a subsequent H. contortus infection.

The effect of host age and inoculation dose on infection dynamics of Angiostrongylus vasorum in red foxes (Vulpes vulpes)

BackgroundInfections and clinical cases of Angiostrongylus vasorum in dogs are found increasingly across Europe, thus rendering knowledge on its infection biology more important. We used red foxes as a carnivore model to examine the effect of host age and infection dose on the establishment of adult A. vasorum in single experimental infections.MethodsFourteen juvenile and fourteen adult red foxes, free of metastrongyloid infections, were given a low (50) or high (200) dose of third-stage larvae (L3) of A. vasorum. Two groups of three foxes of each age group served as uninfected controls. Larval excretion by Baermann and blood parameters were followed for ten weeks. Worm counts were performed at necropsy by sequential perfusion, dissection and Baermann method.ResultsThe establishment rate (i.e. recovery in percentage of inoculation dose) of A. vasorum primary infections in red foxes was associated with host age and inoculation dose. In the low dose juveniles, 61% (range 52–72%) of the infection dose was recovered as worms in the pulmonary arteries and heart at necropsy while only 35% (21–50%) were recovered in the high dose. Corresponding establishment rates for adults were 39% (18–98%) and 8% (1–21%). In juveniles, a higher dose resulted in significantly higher adult worm counts, higher larval excretion and more pronounced pathophysiological changes, particularly in coagulation parameters. Earlier onset of patency was also found in the juveniles. In contrast, the larval excretion in high dose adults was very low and two infected animals never reached patency. However, a few adults showed only limited resistance as judged by excretion of larvae. The increase to very high larval excretion levels (> 4,000 larvae per g of faeces) after several months in a single animal, indicated that any potential acquired immunity does not affect worm fecundity.ConclusionsResistance to a primary A. vasorum infection was generally higher in older animals, and this age resistance was reflected in lower worm counts and reduced excretion of larvae. The juvenile red foxes were fully susceptible, as reflected in high establishment rates. Although severe clinical disease was never observed in the foxes, A. vasorum infections in red foxes appear to be chronic and moreover, to resemble infections in dogs. The results underline the red fox as a suitable model as well as natural reservoir for the parasite.