Internal parasites of possums (Trichosurus vulpecula) from Kawau Island, Chatham Island and Stewart Island

As part of a search for pathogens that might be useful agents for biological control of possums, the three largest offshore islands of New Zealand that still have possums were surveyed to determine the pathogens present in these isolated populations. Brushtail possums from Kawau Island (n = 158), Chatham Island (n = 214) and Stewart Island (n = 194) were examined for internal parasites. Possums from Kawau Island were infected with Eimeria spp. (16.7%), Bertiella trichosuri (5.2%) and Purustrongyloides trichosuri (15.5%). No Paraustrostrongylus trichosuri or Trichostrongylus spp. were found. Possums from Chatham Island were infected with Eimeria spp. (10.9%). Bertiella trichosuri (3.6%), T colubriformis (6.6%), T retortaeformis (1%) and T. vitrinus (0.5%). No Parastrongyloides or Paraustrostrongylus spp. were found. Possums from Stewart Island were infected only with Eimeria spp. (4.6%). Because of their paucity of some parasites, the opportunity exists to use these offshore islands to study the introduction and spread of a parasite into a possum population, and what technology would be required to bring it to hyperendemicity.     

Endoparasites of brushtail possums (Trichosurus vulpecula) from the South Island,New Zealand

As part of a study to assess whether endoparasites could assist in the biological control of brushtail possums in New Zealand, we investigated the composition and distribution of possum endoparasites in the South Island. Possums were collected near five of the original release areas in the South Island: Banks Peninsula, Hokitika, Nelson, Dunedin and Invercargill.

Among the nematodes, those most frequently encountered were Trichostrongylus spp., which were present in possums from all five study areas. Trichostrongylus species from possums in the Invercargill area comprised 4.5% T. colubriformis, 0.9% T. vitrinus and 11.3% T. retortaeformis. Paraustrostrongylus trichosuri and Parastrongyloides trichosuri were found only in the Invercargill area, where they infected 1.4% and 14% of possums respectively. The cestode Bertiella trichosuri was present in possums from all locations except Dunedin. The protozoan Eimeria spp. occurred in all areas.

These are the first records of Parastrongyloides trichosuri, Paraustrostrongylus trichosuri, T. vitrinus, T. retortaeformis and Eimeria spp. in South Island possums.

The prevalence of endoparasites and the intensity of infection was very low compared to the lower North Island of New Zealand. Endoparasites at the existing levels in the South Island probably have very little effect on possum populations.     

Endoparasites of brushtail possums (Trichosurus vulpecula) from the South Island, New Zealand

As part of a study to assess whether endoparasites could assist in the biological control of brushtail possums in New Zealand, we investigated the composition and distribution of possum endoparasites in the South Island. Possums were collected near five of the original release areas in the South Island : Banks Peninsula, Hokitika, Nelson, Dunedin and Invercargill. Among the nematodes, those most frequently encountered were Trichostrongylus spp., which were present in possums from all five study areas. Trichostrongylus species from possums in the Invercargill area comprised 4.5% T. colubriformis, 0.9% T. vitrinus and 11.3% T. retortaeformis. Paraustrostnmgylus trichosuri and Parastrongyloides trichosuri were found only in the Invercargill area, where they infected 1.4% and 14% of possums respectively. The cestode Bertiella trichosuri was present in possums from all locations except Dunedin. The protozoan Eimeria spp. occurred in all areas. These are the first records of Parastrongyloides trichosuri, Paraustrostrongylus trichosuri, T. vitrinus, T. retortaeformis and Eimeria spp. in South Island possums. The prevalence of endoparasites and the intensity of infection was very low compared to the lower North Island of New Zealand. Endoparasites at the existing levels in the South Island probably have very little effect on possum populations.     

Metastatic mineralisation in brushtail possums (Trichosurus vulpecula) from Kawau Island

AIMS: To describe the nature and incidence of metastatic mineralisation in brushtail possums (Trichosurus vulpecula) caught on Kawau Island. METHODS: Wild-caught possums were individually housed in captivity over a 24-month period and fed a cereal-based mash diet. Possums that became debilitated were examined post mortem for evidence of metastatic mineralisation of the heart, major blood vessels and kidneys. Serum and aortic segments were collected from affected animals and were analysed for mineral composition. Non-debilitated animals and possums that were experimentally poisoned with cholecalciferol were examined as a comparison. RESULTS: Fifteen of 42 possums (36%) captured on Kawau Island and housed in captivity were debilitated as a result of metastatic mineralisation of the walls of the aorta and/or of the kidney tubules, with four further possums having evidence of mineralisation when humanely killed. Phosphate and ammonium deposits were found in the aorta, and calcium deposits in the kidney tubules. Serum phosphorus and calcium levels were elevated in the debilitated animals. Similar lesions were found in only one of 288 possums captured from other North Island areas and housed in captivity over the same time period. CONCLUSION: Possums from Kawau Island appear to be more predisposed to metastatic mineralisation than possums from other areas of the North Island. The lesions observed in these possums were similar to those caused by cholecalciferol poisoning.     

Coccidia (protozoa : sporozoasida) of cats and dogs IV. Identity and prevalence in dogs

Examination of 481 faecal samples from North Island dogs revealed that 307 (63.8%) contained coccidia. The majority of infected samples contained a single coccidian but in total 4 valid coccidian parasites of dogs were identified. Two further coccidians, accidentally “parasitic” in dogs, were tentatively identified. The identities and prevalences of the valid coccidian parasites were — Isospora canis (4.0%), Isospora ohioensis (9.2%), Hammondia heydorni (2.7%), Sarcocystis spp. (58.8%); and of the accidental coccidian “parasites” — Isospora lacazei (2.1%), Eimeria spp. (9.8%).     

Allergic tests on cattle vaccinated against Johne's disease

Giardia intestinalis cysts were detected in faeces from 12.9% of 124 brushtail possums (Trichosurus vulpecula) trapped in Auckland, Hawke's Bay, the Wairarapa and Wellington; in faecal material from 61.0% of 77 ship rats (Rattus rattus) from areas of Auckland, Hawke's Bay and Wellington; and in faecal material from 25.3% of 182 house mice (Mus musculus) from the North Island. Possums and rodents in forested areas of Auckland and Wellington city water catchments were infected. The role of wild animals in maintaining and spreading Giardia in New Zealand is discussed.     

Giardia intestinalis in North Island possums, house mice and ship rats

Giardia intestinalis cysts were detected in faeces from 12.9% of 124 brushtail possums (Trichosurus vulpecula) trapped in Auckland, Hawke's Bay, the Wairarapa and Wellington; in faecal material from 61.0% of 77 ship rats (Rattus rattus) from areas of Auckland, Hawke's Bay and Wellington; and in faecal material from 25.3% of 182 house mice (Mus musculus) from the North Island. Possums and rodents in forested areas of Auckland and Wellington city water catchments were infected. The role of wild animals in maintaining and spreading Giardia in New Zealand is discussed.     

Anthelmintics for the control of nematode infections in the brushtail possum (Trichosurus vulpecula)

AIMS: To determine the efficacy of eprinomectin, doramectin and a combination of albendazole and levamisole in suppressing or eliminating nematode infections or faecal egg counts (FEC) in possums naturally or experimentally infected with Parastrongyloides trichosuri, Paraustrostrongylus trichosuri and Trichostrongylus colubriformis. METHODS: To establish an effective dose of eprinomectin, groups of naturally infected possums were treated with 0, 0.5, 2.5, 5.0 or 7.5 mg/kg liveweight (LW) eprinomectin pour-on (n=6 possums/group) and changes in FEC and nematode worm counts at necropsy determined, 18 days later. Efficacy of the 7.5 mg/kg dose was re-examined in a second group of naturally infected possums (n=12) by monitoring FEC weekly for 28 days post-treatment. Persistence of the anthelmintic effect of doramectin injection was tested using nematode-free possums treated with 0, 0.2, 0.4, 0.6 or 0.8 mg/kg LW (n=3 possums/ group), which were experimentally infected 14 days later with T. colubriformis, Paraustrostrongylus trichosuri and Parastrongyloides trichosuri infective larvae. Response to treatment was assessed by FEC and nematode worm counts at necropsy, 42 days posttreatment. Efficacy of a 1.0 mg/kg dose of doramectin was subsequently examined using naturally infected possums (n=11) by monitoring FEC weekly for 28 days post-treatment. To determine the efficacy of a levamisole-albendazole combination drench, possums with naturally acquired nematode infections (n=6) were treated orally with 37.5 mg/kg LW levamisole plus 23.75 mg/kg LW albendazole on 2 occasions, 7 days apart, and response to treatment was assessed by monitoring FEC for 57 days. RESULTS: Eprinomectin 7.5 mg/kg LW reduced Paraustrostrongylus trichosuri worm counts by 98 % (p<0.05). Doramectin 0.6 mg/kg LW reduced Parastrongyloides trichosuri and Trichostrongylus spp worm counts by 99% (p<0.05) and 0.8 mg/kg LW reduced Paraustrostrongylus trichosuri by 100% (p<0.05), in possums challenged with larvae 14 days after treatment. Treating possums with a levamisole-albendazole combination orally, twice, 7-days apart, reduced FEC by 99%. CONCLUSIONS: The doses of anthelmintics required to effectively control nematodes in possums were higher than those recommended for animals for which they are currently registered. Possums tolerate the high dose rates of anthelmintics used in this study without apparent adverse effects.     

Concurrent avian malaria and avipox virus infection in translocated South Island saddlebacks (Philesturnus carunculatus carunculatus)

Abstract

CASE HISTORY: Outbreaks of mortality in South Island saddlebacks (Philesturnus carunculatus carunculatus) that had been translocated to two offshore islands in the Marlborough Sounds of New Zealand were investigated during the summer of 2002 and 2007. Both outbreaks were associated with a severe decrease in numbers of saddlebacks of up to 60% of approximately 200 birds.

CLINICAL AND PATHOLOGICAL FINDINGS: Many of the surviving birds were in poor condition, and had skin lesions on the legs and head. Necropsy showed pale liver and lungs, and a swollen spleen. Histopathology revealed schizonts resembling Plasmodium spp. within the cytoplasm of many hepatocytes and splenic histiocytes. The skin lesions consisted of epithelial proliferations containing numerous Bollinger bodies typical of avipox virus (APV) infection. Two different APV were isolated, using PCR, from two different birds exhibiting skin lesions. Each isolate had 100% sequence homology with APV members from either Clade A or Clade B. In addition, PCR analysis revealed that the Plasmodium elongatum present in infected birdsbelonged to a strain that was endemic in the population of North Island saddlebacks (Philesturnus carunculatus rufusater).

DIAGNOSIS: Concurrent infections with Plasmodium spp. haemoparasites and APV were identified as the likely cause of death in the birds examined.

CONCLUSIONS AND CLINICAL RELEVANCE: Although the Plasmodium spp. identified is thought to be endemic to saddlebacks in New Zealand, the affected birds were likely to be immunocompromised by concurrent APV infection or through lack of genetic diversity. Both the introduced mosquito Culex quinquefasicatus and the native mosquito Culex pervigilans are likely vectors for both these diseases, and the provision of water supplies less favourable to mosquito-breeding is recommended.     

Avian haemosporidian parasites infection in wild birds inhabiting Minami-daito Island of the Northwest Pacific, Japan

Haemosporidian parasites infection among wild birds inhabiting Minami-daito Island was studied. Blood films from 183 birds representing 4 species of 4 families were examined microscopically. Avian haemosporidian parasites were detected in 3 species with an overall prevalence of 59.6%. None of the 30 Daito scops owls (Otus scops interpositus) examined were infected. Either Haemoproteus sp. or Plasmodium sp. infection was found in 14 of 31 (45.2%) Borodino islands white-eyes (Zosterops japonicus daitoensis). Plasmodium spp. were found in 94 of 102 (92.2%) bull-headed shrikes (Lanius bucephalus) and 1 of 20 (5%) tree sparrows (Passer montanus).     

Ascaridoid nematodes and associated lesions in stomachs of subadult male northern fur seals (Callorhinus ursinus) on St. Paul Island, Alaska: (1987-1999).

Stomachs from subadult male northern fur seals (SAMs) (Callorhinus ursinus) (n = 5,950) from St. Paul Island, Alaska, were examined from 1987 to 1999 for lesions and parasites. On gross examination of these stomachs, parasite nodules were evident in 92% of the stomachs and active and healing ulcers were found in 14% and 10%, respectively. Prevalence of nematodes from 1987 to 1997 was 88% for 5,700 SAMs for which numbers of parasites were estimated but not identified to the genus level. All nematodes recovered from 250 SAMs examined in 1998 (n = 124; 99% infected) and in 1999 (n = 126; 91% infected) were identified and counted. Prevalences in 1998 and 1999 were 5% and 0% for Anisakis spp., 52% and 18% for Contracaecum spp., and 96% and 89% for Pseudoterranova spp., respectively.     

Prevalence and Significance of Parasites of Horses in Some States of Northern Nigeria

This study was conducted to determine the prevalence and significance of parasites of horses in northern Nigeria. Blood and faecal samples were randomly collected from 243 horses from different stables in some states of northern Nigeria for laboratory analyses. Fifty-seven horses (23.5%) were found infected with parasites. The hemoparasites detected, 21 (8.6%), include Theileria equi, Babesia caballi, Trypanosoma vivax and Trypanosoma evansi. The endoparasites encountered, 29 (11.9%) were Strongylus spp., Strongyloides spp., Oxyuris equi, Parascaris equorum, Paragonimus spp. and Dicrocoelium spp., 3 (1.2%) was Eimeria spp. Four horses (1.6%) had mixed infection of hemo- and endoparasites. This preliminary finding shows that parasitism is a problem in the horse stables examined, and calls for proper stable hygiene, routine tick control and regular deworming programme.     

Prevalence and risk factors associated with intestinal parasites in pigs in Chongqing, China

From 2007 to 2009, the prevalence of intestinal parasites was investigated in intensive and extensive pig farms in Chongqing, China. A total of 2971 samples from both sexes and five age categories (breeding boars, breeding sows, fatteners, growers and weaners) were evaluated by standard methods for the presence of helminth ova and protozoan oocysts, cysts and/or trophozoites. Of the 2971 pigs sampled, 362(12.18%) were infected with Ascaris suum, 301(10.13%) with Trichuris suis, 301(10.13%) with Oesophagostomum spp., 491(16.53%) with Eimeria spp., 149(5.02%) with Isopora suis, 677(22.79%) with Balantidium coli and 196(6.60%) with Cryptosporidium spp. Growers had the highest infection rate while breeding boars had the lowest among the five age categories. B. coli was the most common protozoan in all pig age groups. Pigs infected with multiple parasites were common. Risk factors such as management methods, seasons, ages, etc. can influence the infection rate to a certain degree. This investigation provides relevant data about risk factors for pig farmers, thus allowing them to make more appropriate antiparasitic treatments according to farm conditions and local climate in Chongqing.     

Distribution of leptospirosis in possums from New Zealand and its offshore islands

Extract

As part of a larger project investigating methods of brushtail possum (Trichosurus vulpecula) biocontrol, possum sera were collected from 15 sites throughout New Zealand and its offshore islands. These sites were selected to cover the original release sites of possums in New Zealand.     

Cow–Calf Herds in Eastern Germany: Status Quo of Some Parasite Species and a Comparison of Chemoprophylaxis and Pasture Management in the Control of Gastrointestinal Nematodes

Infections with gastrointestinal parasites (Eimeria spp., Cryptosporidium spp., Buxtonella sulcata, Fasciola hepatica, Moniezia spp. and trichostrongyles) and lungworms were monitored in five cow–calf herds in the north German lowlands. Estimated prevalences of infections with Eimeria spp. (predominantly Eimeria bovis) ranged between approximately 2 and 48 %. The highest prevalences were found during late summer and autumn. On one farm Cryptosporidium spp. were detected in July and August (prevalence: 8.5 ± 2.7 % and 6.7 < 2.0 %). The latter finding coincided with diarrhoea in many calves. Buxtonella sulcata was found during the entire study period in highly variable estimated prevalences ranging between zero and 73 %, but without any obvious association with clinical disease. Fasciola hepatica was detected on four out of five farms at estimated prevalences of approximately 1–20 %. Lungworm infections played a minor role in at least three of five study herds. The estimated prevalence of trichostrongyle infections rose from August until November whereas the intensity of infection did not change significantly. No difference in the intensity of infection could be detected between one farm on which infections with gastrointestinal nematodes were controlled only by moving the animals to an uninfected pasture in July, and three other herds on which strategic anthelmintic control was in place.     

Lung worm (Marsupostrongylus spp.) infection in common brushtail possums (Trichosurus vulpecula)

Marsupostrongylus spp. are the metastrongyloid nematodes most commonly associated with verminous pneumonia in Australian marsupials. Currently, there is a scarcity of information regarding this parasite in the common brushtail possum (Trichosurus vulpecula). Thirty-four free-living possums submitted to two wildlife hospitals in Sydney, Australia, between 2008 and 2015 were diagnosed with verminous pneumonia on postmortem examination. The majority of possums presented ill with multiple comorbidities. However, only five cases had clinical signs of respiratory disease. Necropsy and histopathology revealed extensive lung lesions characterised by diffuse, mixed interstitial infiltrates of macrophages, lymphocytes and plasma cells with mild to marked concentrations of eosinophils. Bronchopneumonia, pulmonary oedema, interstitial fibrosis, atelectasis and type II pneumocyte hyperplasia were also present in most cases. Adult nematodes, first-stage larvae and embryonating eggs were present in the large airways and alveolar spaces. The parasites were definitively identified as Marsupostrongylus spp. in eight cases with presumptive diagnoses based on histopathological characteristics reached in a further 26 cases. Twenty-nine of the 34 affected possums were adults with no sex predisposition. A review of the brushtail possum records at Taronga Wildlife Hospital from 1999 to 2015 revealed no lungworm infections were reported in the 45 possums examined before 2008. However, between 2008 and 2015, 30 of 47 possums (63.8%) examined were diagnosed with metastrongyloid lungworms. This case series is the first detailed report of Marsupostrongylus nematodes in common brushtail possums and highlights the clinical and pathological features, along with epidemiological findings.     

Molecular phylodiagnosis of Echinococcus granulosus sensu lato and Taenia hydatigena determined by mitochondrial Cox1 and SSU-rDNA markers in Iranian dogs: Indicating the first record of pig strain (G7) in definitive host in the Middle East

Unawareness of canine parasitic diseases among at-risk hosts and an uncontrolled program of stray dog population have caused that zoonotic parasites received great attention in endemic regions of the Middle East. A total of 552 faecal samples were collected between December 2016 to January 2018 from stray (n = 408) and domestic (n = 144) dogs of Iran. All specimens were coproscopically observed following concentration and flotation techniques. Subsequently, the DNAs of taeniid eggs were extracted, amplified, and sequenced by targeting of mitochondrial cytochrome oxidase subunit 1 and small-subunit ribosomal DNA markers. The overall prevalence of canine intestinal parasites found 53.6%. The following parasites and their total frequencies were identified: taeniid (10.5%), Dicrocoelium dendriticum (0.7%), Trichuris vulpis (1.2%), Capillaria spp. (2.3%), Blastocystis spp. (5.2%), Ancylostoma spp. (2%), Eimeria spp. (13.2%), Dipylidium caninum (2.3%), Toxocara canis (3.8%), Giardia spp. (8.5%), and Toxascaris leonina (3.6%). Stray dogs were characterized more likely to be poliparasitized and indicated a higher prevalence of taeniid (10.9%), T. canis (4.4%) Giardia spp. (10.1%) than domestic dogs (P > 0.05). Phylogenetic and sequence analysis of Cox1 and SSU-rDNA indicated a low genetic diversity (Haplotype diversity; 0 to 0.495) in E. granulosus sensu lato G1, G3, G7 genotypes, and Taenia hydatigena. The pairwise sequence distances between G7 isolates showed an intra-diversity of 0.7%–1.5% and identity of 98.5%–100%. The first occurrence of pig strain (G7) from Iranian dogs might have substantial implications in the drug treatment of infected dogs due to the shorter maturation time of G7 compared with G1 genotype. Thus, the preventive strategies should be noticed to determine the risk factors, the importance of applying the hygienic practices, and well adjusting deworming programs for the Iranian dogs and at-risk individuals.     

Prevalence of anthelmintic resistance on 62 beef cattle farms in the North Island of New Zealand

AIM: To establish the prevalence of anthelmintic resistance in parasitic nematodes on a random sample of beef cattle herds in the North Island of New Zealand.

METHODS: A cross-sectional prevalence study was conducted using a standardised faecal nematode egg count (FEC) reduction (FECR) test (FECRT) for ivermectin, levamisole and albendazole on 60 calves on each of 62 farms in the North Island chosen at random from farms that conformed with the selection criteria. Resistance to an anthelmintic was inferred when there was <95% reduction in FEC 7-10 days after treatment. Larval cultures were performed for all control groups and for treated groups for which resistance was evident.

RESULTS: Of the farms that completed the FECRT, 4/61 (7%) showed ≥95% reduction in FEC for all anthelmintics tested. Resistance to ivermectin was evident on 56/61 (92%) farms, to albendazole on 47/62 (76%) farms, and to both ivermectin and albendazole on 45/61 (74%) farms. Resistance to levamisole was evident on only 4/62 (6%) farms. The parasites most prevalent in resistant populations cultured were Cooperia spp. On 45/61 (74%) farms where Cooperia spp were present in suffi cient numbers, resistance to both ivermectin and albendazole was evident. No cases of levamisole-resistant Cooperia spp were detected. Resistance of Ostertagia spp to ivermectin was evident on 4/45 (9%) farms, to albendazole on 15/46 (35%) farms, and to levamisole on 4/46 (9%) farms.

CONCLUSION: Anthelmintic resistance in parasitic nematodes of cattle is common in the North Island of New Zealand. Beef farmers need to be aware of the risks posed by anthelmintic resistance, and routine FECR testing is recommended to ensure optimal productivity and to guide decision-making when purchasing anthelmintics to be used on-farm.     

Prevalence of Eimeria spp. in Sows at Piglet‐producing Farms in Germany

The prevalence of Eimeria infections was investigated in an initial survey in 54 sow herds of small (five sows) to large (1600 sows) size by random sampling (n = 1204). All sows of four Eimeria‐positive medium‐sized farms (63 or 130 sows) were re‐examined 40–99 days after the first visit. A follow‐up survey over the whole reproductive cycle was subsequently performed in a positive herd of 130 animals where faecal samples of 43 sows were repeatedly collected on seven successive farm visits. In 44 farms (81.5%) parasite stages (eggs of strongylids, Trichuris, Ascaris, Strongyloides, oocysts of Eimeria and Isospora) were identified in sow faeces, strongylids being the most prevalent intestinal parasites (34 farms resembling 63%) followed by Eimeria spp. (28 farms resembling 52%). Of the 1204 random samples collected during the initial survey 8.6% contained Eimeria oocysts. Oocysts of E. polita and E. debliecki were present in each of 25 Eimeria‐positive samples selected for species differentiation. Eimeria suis was diagnosed in 84%, E. scabra in 60%, E. porci in 52%, E. perminuta in 49% and E. spinosa in 20% of these specimens. At the second visit the prevalence rates of Eimeria infections had either increased or decreased. In the follow‐up study Eimeria infections were found to be most frequent (82%) at the service station. At the quarantine unit and the gestation stable 50 and 48% of the 43 sows were Eimeria positive. The lowest prevalence of Eimeria infection was observed in the farrowing unit (14%). With respect to the reproductive state of the sows highest infection rates were seen 2 weeks after weaning (72%) continuously decreasing until 2 weeks after farrowing (14%). A periparturient rise of oocyst excretion was not observed. The infestation rate remained low until 1 week before weaning (16%). Low infection intensities clearly dominated. Clinical disease was not associated with Eimeria infection.