In Vitro Evaluation of Ozonated Water Treatment on the Viability of Eimeria Oocysts and Giardia Cysts from Water Buffaloes: A Proof-of-Concept Study.

The aim of this proof-of-concept study was to evaluate the in vitro effects of ozonated water treatment on the viability of Eimeria oocysts and Giardia cysts isolated from naturally infected water buffaloes. Eimeria oocysts were divided into seven groups of six replicates that were treated with ozonated water at three ozone concentrations (0.5, 1, and 2 mg/L) and two contact times (five and ten minutes), and one group (negative control) that was exposed to non-treated water. Giardia cysts were divided into nine groups of six replicates and were treated with ozonated water at four ozone concentrations (0.1, 0.3, 0.5, and 1 mg/L) and two contact times (one and two minutes), while one group (negative control) was exposed to non-treated water. The results of the ozonated water treatment gave a 33% inhibition of the sporulation of Eimeria oocysts and rendered 96.3% of Giardia cysts non-viable, suggesting that ozonated water treatment could be a promising alternative sanitation technology to common conventional disinfectants for reducing intestinal protozoa infections in water buffaloes; though further in vitro and in vivo tests are needed.

Analysis of caecal mucosal inflammation and immune modulation during Anoplocephala perfoliata infection of horses.

Anoplocephala perfoliata is the commonest equine tapeworm, the adult parasites are attached in groups close to the ileocaecal valve causing marked inflammatory pathology. This work aimed to characterize the nature of the in vivo mucosal immune response to A perfoliata, and to investigate the role of A perfoliata excretory-secretory components in modulating in vitro immune responses. Real-time PCR detected elevation of IL13 and TGFß transcription in early-stage A perfoliata infection. In late-stage infection, IL-13, IL4 and Ifn transcripts were reduced while the regulatory cytokines, TGFß, IL10 and the transcription factor FOXP3 were increased in tissue close to the site of A perfoliata attachment; indicating downregulation of T-cell responses to A perfoliata. In vitro, A perfoliata excretory-secretory products induced apoptosis of the Jurkat T-cell line and premature cell death of ConA stimulated equine peripheral blood leucocytes. Analysis of cytokine transcription patterns in the leucocyte cultures showed a marked inhibition of IL-1 and IL-2 suggesting that a lack of T-cell growth factor transcription underlies the mechanism of the induced equine T-cell death. These preliminary findings suggest A perfoliata may have the ability to down-regulate host T-cell responses.

The recovery of added nematode eggs from horse and sheep faeces by three methods.

BACKGROUND: Nematode infections in horses are widespread across the world. Increasing levels of anthelmintic resistance, reported worldwide in equine parasites, have led to the creation of programs for the control of nematodes based on faecal egg counts (FEC). To improve nematode egg counting in equine faecal samples and establish whether the matrix of equine faeces or the eggs affect the counts, the analytical sensitivity, accuracy and precision of Mini-FLOTAC (combined with Fill-FLOTAC), McMaster and Cornell-Wisconsin techniques were compared. Known numbers of eggs extracted from equine or ovine faeces were added to egg free ovine and equine faeces to give counts of 10, 50, 200 and 500 eggs per gram (EPG) of faeces. RESULTS: The Cornell-Wisconsin significantly underestimated egg counts and McMaster showed a low analytical sensitivity, revealing 100% of sensitivity only for concentrations greater than 200 EPG. EPG values detected by Mini-FLOTAC did not differ significantly from expected counts at any level of egg density. CONCLUSIONS: Mini-FLOTAC combined to Fill-FLOTAC which provides an accurate method of weighing without need for a balance and filtering out debris, could be used for FEC on the farm as well as in the laboratory.

Cross-sectional study of Fasciola gigantica and other trematode infections of cattle in Edu Local Government Area, Kwara State, north-central Nigeria.

BACKGROUND: Trematode infections of livestock are of global veterinary and public health importance causing serious economic losses. Majority of data on burden of trematode infections in Nigeria are based on abattoir surveys and there are very few data on herd level risk factors. The present study investigated the prevalence of, and herd level risk factors for, fasciolosis and other trematode infections in cattle in Edu Local Government Area (LGA). METHODS: A cross-sectional survey used two-stage study design to investigate cattle belonging to 65 households. Two questionnaires were administered for household-level and individual cattle-level data. Faecal and blood samples were obtained from the cattle. Logistic regression analyses were performed to determine risk factors for infections. RESULTS: Of 686 faecal samples analysed, 74.9 %, 16.1 %, 7.3 % and 1.2 % were positive for infections with Fasciola gigantica, paramphistomes, Dicrocoelium hospes and Schistosoma bovis respectively. Fasciola gigantica had higher prevalence in adult cattle (77.3 %) than weaners (62.5 %). Majority of co-infections was a combination of F. gigantica with paramphistomes 84/130 (64.6 %). Most (58.9 %) of the cattle belonged to FAMACHA© score 2. The mean packed cell volume (PCV) was 34.4 %. The sensitivity and specificity of FAMACHA© for anaemia (PCV < 24 %) were 18.2 and 96.9 %, respectively. Positive correlation was obtained between faecal egg counts for F. gigantica and paramphistomes (R = 0.15, P = 0.0001). Adult cattle were more likely to be infected with F. gigantica (odds ratio, OR: 1.94; Confidence Interval, CI: 1.19-3.16) than weaners. Cattle belonging to household heads aged between 40-59 years were more likely infected with paramphistomes (OR: 1.95; CI: 1.02-3.74) than those belonging to other age groups. Cattles from herds with size ≥ 100 were more likely infected with D. hospes than those from smaller herds (OR: 6.98; CI: 2.94-16.6). CONCLUSION: This study revealed high prevalence of infection with F. gigantica in Kwara State. The co-infections by F. gigantica and paramphistomes with a positive correlation should be considered during anthelmintic therapy. There is a need to optimise and validate the FAMACHA© for use in cattle based on breeds and variation in colour of ocular mucous membrane. Risk factors identified could assist in tailoring control strategies for various trematode infections to particular groups of farmers and cattle.

Associations between trematode infections in cattle and freshwater snails in highland and lowland areas of Iringa Rural District, Tanzania.

The epidemiology of trematode infections in cattle was investigated within highland and lowland areas of Iringa Rural District, in southern Tanzania. Fecal samples were collected from 450 cattle in 15 villages at altitudes ranging from 696 to 1800 m above the sea level. Freshwater snails were collected from selected water bodies and screened for emergence of cercariae. The infection rates in cattle were Fasciola gigantica 28·2%, paramphistomes 62·8% and Schistosoma bovis 4·8%. Notably, prevalence of trematode infections in cattle was much higher in highland (altitude > 1500 m) as compared with lowland (altitude < 1500 m) areas and was statistically significant (P-value = 0·000) for F. gigantica and paramphistomes but not for S. bovis. The snails collected included Lymnaea natalensis, Bulinus africanus, Bulinus tropicus, Bulinus forskali, Biomphalaria pfeifferi, Melanoides tuberculata and Bellamya constricta with a greater proportion of highland (75%) than lowland (36%) water bodies harbouring snails. Altitude is a major factor shaping the epidemiology of F. gigantica and paramphistomes infections in cattle in Iringa Rural District with greater emphasis upon control needed in highland areas.

The comparison of FLOTAC, FECPAK and McMaster techniques for nematode egg counts in cattle.

Three methods, FLOTAC, FECPAK and McMaster were compared for accuracy and sensitivity for counting numbers of nematode eggs in faeces of naturally infected cattle with high or low nematode egg counts. Only FLOTAC gave positive results for 12 replicates from pooled samples with low egg counts making it more sensitive than FECPAK (67%) and McMaster (41.7%). FLOTAC resulted in generally higher egg counts and lower coefficients of variation than the other two methods used. The reliability of FECPAK and McMaster is depended on the area under the slide counted. All three methods can be used for making decisions whether to treat but FLOTAC or Mini-FLOTAC should be used for faecal egg count reduction tests when lower egg counts are present.

Mini-FLOTAC, a new tool for copromicroscopic diagnosis of common intestinal nematodes in dogs.

BACKGROUND: The most common intestinal nematodes of dogs are Toxocara canis, hookworm and Trichuris vulpis. The present study was aimed to validate a new copromicroscopic technique, the Mini-FLOTAC and to compare its diagnostic efficiency and sensitivity with four other copromicroscopic techniques: direct smear, tube flotation, Wisconsin method and the FLOTAC dual technique. FINDINGS: Two experiments were performed. In the first, faecal positive samples collected from 59 stray asymptomatic dogs, of which 21 were naturally infected with ancylostomidae, 13 naturally infected with T. canis and 25 naturally infected with T. vulpis were used to validate the Mini-FLOTAC technique. The second experiment was performed on faecal samples randomly selected from 38 stray asymptomatic dogs to compare the diagnostic efficiency and sensitivity of the different techniques. Samples were fixed with 5% formalin; sodium chloride and zinc sulphate were used for flotation solutions because they performed best for detecting and quantifying intestinal nematode eggs in dogs. Mini-FLOTAC and FLOTAC were the most efficient and sensitive techniques and they gave higher EPG and higher numbers of positive samples in both the experiments, for all three parasites. CONCLUSIONS: As Mini-FLOTAC does not require centrifugation it is a very promising technique for counting helminth eggs in dog faeces.

Trematode infections in cattle in Arumeru District, Tanzania are associated with irrigation.

BACKGROUND: The relationship between the environment and infection of cattle with trematodes was studied at Arumeru District, Arusha Region, northern Tanzania. Randomly selected villages were grouped into three cattle management strata, (i) zero-grazing (ZZ) (ii) communal grazing without irrigation (ZC) and (iii) communal grazing with irrigation (ZCI). METHODS: Faecal samples were collected from 241 cattle, and processed using the Flukefinder method. Snail intermediate hosts were collected with a snail scoop from the water bodies in the study villages and identified morphologically. RESULTS: The overall prevalence of F. gigantica, paramphistomes and S. bovis were 33%, 37% and 2% respectively. Prevalence for F. gigantica, paramphistomes, and S. bovis for each stratum were, zero-grazing (ZZ) (29.7%, 36.0% and 0%), communal grazing without irrigation (ZC) (6.3%, 15.0% and 3.8%) and communal grazing with irrigation (ZCI) (57.7%, 56.7% and 1.0%) respectively. The differences between strata were significant for F. gigantica (p < 0.001) and paramphistomes (p < 0.05) but not for S. bovis. Irrigation could account for the high prevalence of F. gigantica and paramphistomes in the ZCI stratum as compared to the ZZ and ZC strata. The higher prevalences of F. gigantica and paramphistomes in the ZZ stratum compared with the ZC stratum were unexpected and attributed to the practice of farmers in some ZZ stratum villages buying fodder for their cattle obtained from pastures in ZCI villages. CONCLUSION: Trematode infections in cattle are prevalent in Arumeru District. Fasciola gigantica and paramphistomes are associated with grazing in areas with irrigation of crops. Zero-grazing of cattle does not necessarily prevent the risk of infection.

The maintenance of anthelmintic efficacy in sheep in a Mediterranean climate.

To determine how far management practices on small ruminant dairy flocks in southern Italy have influenced the development of anthelmintic resistance (AR), faecal egg count (FEC) reduction tests were run on 54 sheep farms using the FLOTAC technique with a sensitivity of 2 eggs per gram of faeces. Tests were run on groups of sheep (12-20 animals per group) using six anthelmintics administered orally: levamisole on 8 farms, ivermectin (half and full dose) on 8 farms, moxidectin on 3 farms, monepantel on 8 farms, netobimin on 22 farms (pooled samples) and albendazole on 5 farms (pooled samples). Different formulae and statistics were used to calculate FEC reductions and confidence intervals based on the presence of a control group and/or the use of pooled samples. A very high average efficacy was obtained with all anthelmintics tested as follows: levamisole 99.3% (range across farms 98-100%), ivermectin half dose 99.5% (98.0-100%), ivermectin full dose 99.9% (99.3-100%), moxidectin 100% (99.9-100%), monepantel 99.4% (97-100%), netobimin 99.1% (92-100%) and albendazole 100%. The results suggest that the development of AR in small ruminants could be limited in countries with a Mediterranean type of climate provided that refugia of the nematode populations are maintained, anthelmintic use is restricted and movement of animals is not permitted to spread resistance.

Systemic and mucosal IgE antibody responses of horses to infection with Anoplocephala perfoliata.

Infection of horses with Anoplocephala perfoliata induces a severe inflammatory reaction of the caecal mucosa around the site of parasite attachment adjacent to the ileocecal valve. Lesions show epithelial erosion or ulceration of the mucosa with infiltration by eosinophils, lymphocytes and mast cells leading to oedema, gross thickening and fibrosis of the caecal wall. Despite this evidence of an inflammatory reaction to A. perfoliata within the mucosa of the caecum there is little information about the nature of the local immune response to A. perfoliata. An ELISA which assays serum IgG(T) antibodies to A. perfoliata excretory/secretory antigens has been developed as a diagnostic test. However, the specificity of the ELISA remains sub-optimal and the role of other isotypes in the immune response to A. perfoliata has not been reported. This study measured IgA, IgE and IgG(T) antibody responses to A. perfoliata excretory/secretory antigens in sera of 75 horses presented for slaughter. The prevalence of A. perfoliata infection, as confirmed by the presence of parasites in the terminal ileum, caecum or proximal colon, was 55%. A. perfoliata-specific IgG(T) and IgE antibodies were significantly elevated in infected horses compared to controls; IgA antibodies were also detected but did not differ between infected and control horses. Diagnosis by serum IgG(T) ELISA had a sensitivity of 78% and a specificity of 80%, by comparison the serum IgE ELISA had a sensitivity of just 44% with a specificity of 82% and therefore did not provide an improved diagnostic test. Western blots with sera from infected horses demonstrated IgE-binding to at least 10 separate components of excretory/secretory (E/S) antigens. A similar pattern was also found with IgG(T). Around 30% of horses had high levels of serum IgE which bound fucose-containing carbohydrate antigens on the parasite surface but this was unrelated to the presence of A. perfoliata infection. Immunoperoxidase staining detected numerous IgE-positive cells within lymphoid follicles in the caecal mucosa close to the site of A. perfoliata attachment and quantitative RT-PCR detected high levels of IgE transcription in the caecal mucosa of all horses. Mucosal synthesis of antibodies was confirmed by the demonstration of A. perfoliata-specific IgG(T) and IgE in the supernatant of lamina propria explant cultures that discriminated clearly between infected and uninfected horses. We conclude that there is an active immune response to A. perfoliata within the caecal mucosa involving local production of both IgG(T) and IgE antibody isotypes; but it remains unclear whether this immune response can reduce or eliminate parasite burden.

Effect of the in vivo activity of dihydroartemisinin against Schistosoma mansoni infection in mice.

Dihydroartemisinin, formerly known as an antimalarial drug, is the main metabolite of the mother compound artemisinins, as well as of artemether and artesunate. It has been shown that the drug exhibits antischistosomal efficacy against Schistosoma japonicum. The purpose of the current study was to assess the in vivo effect of dihydroartemisinin against Schistosoma mansoni infection in mice. Drugs at a single oral dose of 300 mg/kg were given to mice to assess the efficacy against different developmental stages of the parasite; juvenile and adult S. mansoni were treated with single doses of dihydroarteminisin with different regimens (at 200, 300, 400 or 600 mg/kg) in the stage of drug sensitivity, and the dose-response relationship was assessed; and the effect of multiple doses (at 200, 300 or 400 mg/kg) on juvenile and adult S. mansoni was also observed. The results showed that a single oral dose (300 mg/kg) of dihydroartemisinin reduced total worm burdens by 13.8-82.1% and female worm burdens by 13-82.8%, and the greatest reductions were seen when treatment was given on day 21 post-infection, with total and female worm burden reductions of 82.1% and 82.8%. Administration of a single oral dose of dihydroartemisinin on day 21 post-infection with different drug dosage (at 200, 300, 400 or 600 mg/kg) reduced total worm burdens by 70.3-87.3% and female worm burdens by 73.5-92.4%, depending on dosage. Similar treatments given on day 49 post-infection reduced total worm burdens by 48.7-68.73% and female worm burdens by 63.25-94.6%. There was obvious dose-response relationship of dihydroartemisinin against the schistosomula and adult worms of S. mansoni observed. Administration with dihydroartemisinin at oral doses of 200, 300 and 400 mg/kg, given once on each of days 20-22 post-infection of three successive days, reduced total worm burdens by 88.5-90.1% and female worm burdens by 89.2-92.1%, depending on dosage. Similar treatments given once on each of days 48-50 post-infection reduced total worm burdens by 60-70.3% and female worm burdens by 77.5-94.9%. It is concluded that dihydroartemisinin exhibits in vivo activity against various developmental stages of S. mansoni, particularly the 21-day schistosomula, and there is obvious dose-response relationship of dihydroartemisinin against the schistosomula and adult worms of S. mansoni observed.

Toxicity of a novel suspension concentrate of niclosamide against Biomphalaria glabrata.

As a new suspension concentrate of niclosamide (SCN) was more effective in controlling Oncomelania snails than a wettable powder of the same drug, it was tested against Biomphalaria glabrata. There were no differences in the effect of the suspension concentrate, the wettable powder of niclosamide and ball-milled pure niclosamide against the adult snails, but at after 48h 0.125mg/l SCN killed 100% of eggs compared with 84.3% for WPN and 17.7% for pure niclosamide. Because of the improved handling characteristics of SCN over the other formulations, further field tests on Biompharia and Bulinus species are warranted.

Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes.

The ability to reliably detect anthelmintic resistance is a crucial part of resistance management. If data between countries are to be compared, the same test should give the same results in each laboratory. As the egg hatch test for benzimidazole resistance is used for both research and surveys, the ability of different laboratories to obtain similar results was studied through testing of known isolates of cyathostomins, Haemonchus contortus, Ostertagia ostertagi, and Cooperia oncophora in programs supported by the EU (Cost B16 and FP6-PARASOL). Initial results showed difficulties in obtaining reproducible and similar data within and between laboratories. A series of ring tests, i.e., simultaneous and coordinated rounds of testing of nematode isolates in different laboratories was subsequently performed. By adopting identical protocols, especially the use of deionized water and making dilutions of thiabendazole in dimethyl sulfoxide in the final ring test, laboratories correctly identified both susceptible and resistant isolates. The protocols for the test and preparation of solutions of thiabendazole are described.