Recent reports indicate N. caninum has a possible role in causing abortions in sheep in New Zealand. Knowledge about the mode of transmission of neosporosis in sheep in New Zealand is limited. This study aimed to determine the rate of vertical transmission that would occur in lambs born from experimentally inoculated ewes and to determine if previous inoculation would protect the lambs from N. caninum infection. A group of 50 ewes was divided into 2 groups with one group being inoculated with 5×10(6) N. caninum tachyzoites prior to pregnancy in Year 1. In Year 2, each of these groups was subdivided into 2 groups with one from each original group being inoculated with 1×10(7) N. caninum tachyzoites on Day 120 of gestation. Inoculation of N. caninum tachyzoites into ewes prior to mating resulted in no congenital transmission in lambs born in Year 1 but without further inoculation, 7 out of 11 lambs in Year 2 were positive for N. caninum infection. Ewes that were inoculated in both years resulted in all 12 lambs born in Year 2 being positive for N. caninum infection. This indicates that previous inoculation in Year 1 did not result in any vertical transmission in that year but did not provide any protection against vertical transmission in Year 2. These results suggest that vertical transmission occurs readily once the ewe is infected.
A multilocus sequence analysis using mitochondria-encoded cytochrome c oxidase subunit I (COI), cytochrome B (CytB), NADH dehydrogenase subunit 5 (ND5); nuclear encoded 18S ribosomal RNA (18S) and 28S ribosomal RNA (28S) genes was performed to determine the levels of genetic variation between the closely related species Haematobia irritans Linnaeus and Haematobia exigua de Meijere. Among these five genes, ND5 and CytB genes were found to be more variable and informative in resolving the interspecific relationships of both species. In contrast, the COI gene was more valuable in inferring the intraspecific relationships. The ribosomal 18S and 28S sequences of H. irritans and H. exigua were highly conserved with limited intra- and inter-specific variation. Molecular evidence presented in this study demonstrated that both flies are genetically distinct and could be differentiated based on sequence analysis of mitochondrial genes.
The ultrastructure of sarcocysts of macro- and microscopic species of Sarcocystis was compared from naturally infected water buffalo from India. Grossly visible sarcocysts had walls consisting of cauliflower-like villar protrusions, typical of S. fusiformis. The sarcocyst wall of the microscopic species of Sarcocystis was 6.4 microns thick and consisted of tightly packed conical villar protrusions that were 9.6 microns long and 3.7 microns wide at the base. At approximately 3 microns above the base, the distal two-thirds of the villar protrusion became conical shaped and was bent laterally at an angle of 45 degrees to the sarcocyst surface. The granular layer beneath the villar protrusions was 0.9 microns thick. In S. levinei the granular layer was 1.9 microns thick, the villar protrusions were narrow and it had a highly undulating primary cyst wall. Whether the microscopic S. levinei-like sarcocysts of Indian and Malaysian water buffalo are distinct species of Sarcocystis will require further investigation.
The Tropical Council for Companion Animal Parasites Ltd. (TroCCAP) is a not-for-profit organisation whose mission is to independently inform, guide and make best-practice recommendations for the diagnosis, treatment and control of companion animal parasites in the tropics and sub-tropics, with the aim of protecting animal and human health. In line with this primary mission, TroCCAP recently developed guidelines for the diagnosis, treatment and control of feline and canine parasites in the tropics. The development of these guidelines required unique and complex considerations to be addressed, often inapplicable to developed nations. Much of the tropics encompass middle-to-low income countries in which poor standards of environmental hygiene and large populations of stray dogs and cats coexist. In these regions, a range of parasites pose a high risk to companion animals, which ultimately may place their owners at risk of acquiring parasitic zoonoses. These considerations led to the development of unique recommendations with regard, for example, to deworming and endoparasite testing intervals for the control of both global and 'region-specific' parasites in the tropics. Moreover, the 'off-' or 'extra'-label use of drugs for the treatment and control of parasitic infections is common practice in many tropical countries and many generic products lack manufacturers' information on efficacy, safety, and quality control. Recommendations and advice concerning the use of such drugs and protocols are also addressed in these guidelines. The formation of these guidelines is an important first step towards improving the education of veterinarians specifically regarding best-practice for the diagnosis, treatment and control of canine and feline parasites in the tropics.
A gastrointestinal parasite survey of 411 stray and refuge dogs sampled from four geographical and climactically distinct locations in India revealed these animals to represent a significant source of environmental contamination for parasites that pose a zoonotic risk to the public. Hookworms were the most commonly identified parasite in dogs in Sikkim (71.3%), Mumbai (48.8%) and Delhi (39.1%). In Ladakh, which experiences harsh extremes in climate, a competitive advantage was observed for parasites such as Sarcocystis spp. (44.2%), Taenia hydatigena (30.3%) and Echinococcus granulosus (2.3%) that utilise intermediate hosts for the completion of their life cycle. PCR identified Ancylostoma ceylanicum and Ancylostoma caninum to occur sympatrically, either as single or mixed infections in Sikkim (Northeast) and Mumbai (West). In Delhi, A. caninum was the only species identified in dogs, probably owing to its ability to evade unfavourable climatic conditions by undergoing arrested development in host tissue. The expansion of the known distribution of A. ceylanicum to the west, as far as Mumbai, justifies the renewed interest in this emerging zoonosis and advocates for its surveillance in future human parasite surveys. Of interest was the absence of Trichuris vulpis in dogs, in support of previous canine surveys in India. This study advocates the continuation of birth control programmes in stray dogs that will undoubtedly have spill-over effects on reducing the levels of environmental contamination with parasite stages. In particular, owners of pet animals exposed to these environments must be extra vigilant in ensuring their animals are regularly dewormed and maintaining strict standards of household and personal hygiene.
In 3 urban areas in Selangor, Peninsular Malaysia between 1973 and 1981, blood from 4084 dogs was examined for haematozoa. The following frequencies were found: Babesia gibsoni 17.7%; microfilariae of Dirofilaria immitis 9.6%; Hepatozoon canis 1.2%; B. canis 1.1%; Ehrlichia canis 0.2%; Trypanosoma evansi 0.1%. A detailed examination of B. gibsoni infections and microfilariasis due to D. immitis with regards to monthly distribution, breed frequency, sex and age, revealed that pedigree and non-pedigree dogs were equally susceptible to Babesia and microfilariae infections.
Twelve goats were inoculated with 20,000 infective larvae of Trichostrongylus colubriformis and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. Most of the worms established within the first 3 m of the small intestine. There was little relocation or loss of nematodes after establishment. The worms started to migrate from the mucosa to the lumen 11 days after infection. At 4 DAI, 63% of the worms were still at the late L3 stage; the remainder of the worm population had completed the third moult to the L4 stage. The population at 11 DAI comprised largely young adults. When 21 DAI was reached, about 57% of the female worms had eggs in their uteri.
Twelve goats were inoculated with 40,000 third-stage Haemonchus contortus larvae and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. More worms established in the fundic, than in the middle or pyloric thirds of the abomasum. Early development occurred within the mucosa; emergence into the lumen started between 7 and 11 days after infection. By 4 DAI, all worms had completed the third moult to the L4 stage. At 11 DAI the majority of the worms were adults. A mean of 13.2% of the female worms had eggs in their uteri at 18 DAI; by 21 DAI more than half of the female worms had eggs in their uteri. The development of H. contortus was essentially similar to that described in sheep.
Two laboratory trials were conducted to determine the effect of the addition of spores (conidia) of the nematophagous fungus, Arthrobotrys oligospora, on the development of the ruminant parasite, Strongyloides papillosus, in cultures of bovine faeces. Both studies showed that at a concentration of 2000 conidia/g faeces virtually eliminated infective larvae (> 99% reduction), following 14 days incubation under ideal conditions (25 degrees C and saturated humidity) for free-living development of this parasite species. In one trial, a high level of control was also observed at a 10-fold decrease in conidia concentration (200 spores/g faeces). This work has demonstrated, in principle, that A. oligospora could provide a practical biological control agent against S. papillosus infecting intensively raised young ruminants in the humid tropics/subtropics.
Little is known about the efficacy of cysteine proteinases (CP) as anthelmintics for cestode infections. We examined the effects of CPs on two rodent cestodes, Hymenolepis diminuta and H. microstoma in vitro. Our data showed that naturally occurring mixtures of CPs, such as those found in papaya latex, and relatively pure preparations of fruit bromelain, papain and stem bromelain, were active in vitro against both juvenile, artificially excysted scoleces, as well as against adult worms of both rodent cestodes. Significant dose-dependent reduction in motility, ultimately leading to death of the worms, was observed with both species, and against both freshly excysted scoleces and 14-day old pre-adult worms. The most effective was fruit bromelain (after 30 min of incubation of juvenile H. diminuta and H. microstoma IC50=63 and 74 μM, respectively, and for pre-adult worms=199 and 260 μM, respectively). The least effective was stem bromelain (after 30 min of incubation of juvenile H. diminuta and H. microstoma IC50=2855 and 2772 μM, respectively, and for pre-adult worms=1374 and 1332 μM, respectively) and the efficacies of papaya latex supernatant and papain were between these extremes. In all cases these values are higher than those reported previously for efficacy of CPs against intestinal nematodes, and in contrast to nematodes, all CPs were effective against cestodes in the absence of exogenous cysteine in incubation media. The CPs appeared to attack the tegument resulting in generalised erosion mainly on the strobila. The scolex was more resistant to CP attack but nevertheless some damage to the tegument on the scolex was detected.
Haemonchus species are major gastro-intestinal parasites affecting ruminants across the world. The present study aimed to assess the sympatric species distribution, genetic diversity, population structure and frequency of β-tubulin isotype 1 alleles associated with benzimidazole resistance. Internal transcribed spacer 2 (ITS2) sequences revealed three sympatric species of Haemonchus, H. contortus, H. placei and H. longistipes with 12 distinct genotypes circulating among ruminant hosts in Pakistan. High genetic variability was observed in Pakistani Haemonchus isolates at nicotine amide dehydrogenase subunit 4 (ND4) and cytochrome oxidase subunit 1 (COI) gene loci. Intra-population diversity parameters were higher in H. contortus isolates than H. placei. Phylogenetic analysis of ND4 and COI sequences did not reveal clustering of haplotypes originating from a particular host indicating high rate of gene flow among Haemonchus parasites infecting sheep, goat and cattle in Pakistan. ND4 and COI haplotypes from Pakistan were compared to sequences of Haemonchus isolates from 11 countries to elucidate the population structure. Multidimensional scaling (MDS) plot of pairwise FST derived from 531 ND4 haplotypes revealed clustering together of H. contortus from Pakistan, China, Malaysia and Italy while the isolates from Yemen and United States were found to be genetically distinct. With respect to H. placei, isolates from Pakistan were found to be genetically differentiated from isolates of other countries. The tests for selective neutrality revealed negative D statistics and did not reveal significant deviations in Pakistani Haemonchus populations while significant deviation (P < 0.05) was observed in Brazilian and Chinese H. contortus populations. Median Joining (MJ) network of ND4 haplotypes revealed Yemenese H. contortus being closer to H. placei cluster. β-tubulin isotype 1 genotyping revealed 7.86% frequency of Y allele associated with benzimidazole resistance at F200Y locus in Pakistani Haemonchus isolates.
To determine if toltrazuril was effective in eliminating Neospora caninum infection from congenitally infected lambs. Twenty-eight ewes were allocated to 3 groups where animals in Groups A and B were inoculated with 1 × 10(7)N. caninum tachyzoites on Day 120 of gestation and Group C was maintained as a negative control group. Lambs born from ewes in Group A were treated with toltrazuril (20mg/kg) on Days 0, 7, 14 and 21 after birth. Lambs in Groups B and C were untreated. All lambs in Groups A and B were seropositive at 12 weeks of age. At 12 weeks of age, no differences between lambs in Group A and Group B were observed in serological results (ELISA and western blot), presence of N. caninum-related brain histopathological lesions or the number of organisms detected by qPCR. Group C remained negative for serology, detection of N. caninum DNA as well as histopathology throughout the study. Results indicate that N. caninum congenitally-infected lambs had a continuing infection with N. caninum despite being treated with toltrazuril.
Faecal egg counts were used to study patterns of trichostrongyle infections in sheep and goats according to season, age, pregnancy and lactation on traditional farms in west Malaysia. Haemonchus contortus and Trichostrongylus spp. were the most important strongyles in sheep and in goats, H. contortus, Trichostrongylus spp. and Oesophagostomum spp. were most prevalent. The faecal egg counts of sheep and goats were apparently not influenced by the small seasonal climatic variations. Strongyle infections were acquired at an earlier age in sheep than in goats. Mean faecal egg counts decreased from the age of 8 months onwards in sheep while in goats this occurred from 12-18 months onwards. A periparturient rise in strongyle egg counts was observed in both animal species. Haemonchus contortus was mainly responsible for this rise in faecal egg counts. The results are discussed with reference to control of gastrointestinal strongyle infections in sheep and goats.
Faecal worm egg counts of goats from two farms in Penang Island, West Malaysia, were monitored over a period of 14 months. The faecal egg count pattern followed that of total rainfall. The humid tropical environment was favourable for the development of various species of trichostrongylid nematodes, namely Haemonchus contortus, Trichostrongylus spp., Oesophagostomum spp. and Cooperia spp. Generally, H. contortus was observed to be the predominant species, more so in the monsoon months of the year.
A previous study had suggested that local strains of goat trichostrongyles, comprising largely Haemonchus contortus, might have developed resistance to benzimidazole anthelmintics. A trial involving 18 goats was conducted to confirm this. There was a significant (P < 0.01) reduction in worm burdens in goats given levamisole, but this was not so for those animals given albendazole, fenbendazole, oxfendazole and mebendazole (P > 0.05).
Snapper had been cultured in Malaysia since 1980 due to the fry availability and the high demand. However, details on the caligids infestation were not properly documented. This study was carried out to determine the prevalence, mean intensity and site preference of Caligus rotundigenitalis (Caligidae, Siphonostomatoida) a parasitic copepod on cage cultured crimson snapper, Lutjanus erythropterus from Bukit Tambun, Penang, Malaysia. A total of 70 specimens of cultured snapper were examined based on different infestation sites such as head, body as well as operculum. The specimens were separated into three groups according to the size of the fish. C. rotundigenitalis was found to be the only species infesting L. erythropterus with the prevalence and the mean intensity of 81.4% and 5.6±4.4, respectively. There was a significant difference between the prevalence of site infestation of the body and inner operculum sites. The prevalence of C. rotundigenitalis was highest on inner operculum of the fish followed by the body and head. However, there was no significant difference in the distribution of C. rotundigenitalis over the different infestation sites derived from the three groups. The information obtained from this study can be used for more effective control measures of ectoparasitic copepod infestation in floating cages.
Vector-borne infections are persistent public health threats worldwide. In recent years, a number of mosquito-borne viruses have emerged or re-emerged to cause major disease outbreaks. Other vector-borne pathogens, however, remain understudied and much neglected especially in the developing regions of the world including Southeast Asia. In this study, the brown dog tick Rhipicephalus sanguineus sensu lato, cat louse Felicola subrostratus, and cat fleas Ctenocephalides felis and Ctenocephalides orientis collected from free-ranging cats and dogs in Malaysia were molecularly screened for the presence of Bartonella and Rickettsia bacteria, and Dipylidium tapeworm. Our results showed the presence of Bartonella clarridgeiea, Bartonella henselae (lineage Marseille and lineage Houston-1), and Rickettsia sp. in C. felis. We also detected Rickettsia asembonensis in C. orientis and R. sanguineus s.l. Additionally, this study provides the first documentation on a potentially new species of Dipylidium infecting F. subrostratus and C. felis. Our results highlight the role of ectoparasites from free-ranging animals including cats and dogs, in harboring multiple transmissible pathogens.
The present study investigated the genetic profile of the cosmopolitan cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae) from Malaysia and the reference data available in the National Center for Biotechnology Information (NCBI) GenBank. A set of sequences of 100 Malaysian samples aligned as 550 characters of the cytochrome c oxidase subunit I (cox1) and 706 characters of the II (cox2) genes revealed ten haplotypes (A1-A10) and eight haplotypes (B1-B8), respectively. The concatenated sequences of cox1 and cox2 genes with a total of 1256 characters revealed 15 haplotypes (AB1-AB15). Analyses indicated that haplotype AB1 was the most frequent and the most widespread haplotype in Malaysia. Overall haplotype and nucleotide diversities of the concatenated sequences were 0.52909 and 0.00424, respectively, with moderate genetic differentiation (FST = 0.17522) and high gene flow (Nm = 1.18). The western population presented the highest genetic diversity (Hd = 0.78333, Pi = 0.01269, Nh = 9), whereas the southern population demonstrated the lowest diversity (Hd = 0.15667, Pi = 0.00019, Nh = 3). The concatenated sequences showed genetic distances ranged from 0.08 % to 4.39 %. There were three aberrant haplotypes in cox2 sequences that highly divergent, suggesting the presence of cryptic species or occurrence of introgression. In the global point of view, the aligned sequences of C. felis revealed 65 haplotypes (AA1-AA65) by the cox1 gene (n = 586), and 27 haplotypes (BB1-BB27) by the cox2 gene (n = 204). Mapping of the haplotype network showed that Malaysian C. felis possesses seven unique haplotypes in both genes with the common haplotypes demonstrated genetic affinity with C. felis from Southeast Asia for cox1 and South America for cox2. The topologies of cox1 and cox2 phylogenetic trees were concordant with relevant grouping pattern of haplotypes in the network but revealed two major lineages by which Malaysian haplotypes were closely related with haplotypes from the tropical region.
The anthelmintic efficacy of benzimidazoles, levamisole, closantel, ivermectin and moxidectin was evaluated on an institutional farm in Malaysia using faecal egg count reduction tests, controlled slaughter trials and an in vitro egg hatch assay. The results of this study indicated simultaneous resistance of Haemonchus contortus against benzimidazoles and ivermectin and of Trichostrongylus colubriformis against benzimidazoles and levaminsole on the same farm. Moxidectin was effective against the ivermectin resistant H. contortus.