Progress in extermination of cattle grubs (Hypoderma spp.): Summary of the symposium

A symposium on “Extermination of Cattle grubs (Hypoderma spp.)” was organized at the Seventh International Conference of the World Association for the Advancement of Veterinary Parasitology held at Thessaloniki, Greece, on 14–16 July 1975. The symposium dealt mainly with regional or national programs now operating for examination of cattle grubs in several countries, including Canada, Eire, the Federal Republic of Germany, France, Northern Ireland, Switzerland, and the U.S.S.R. Besides the papers published in this issue, papers were also presented on “Warble Fly Eradication in Eire” (Thornberry, 1975); “Changes in Immune Response to Hypoderma spp. in Cattle Treated With Fenthion” (Boulard, 1975); and “Eradication of Hypodermosis: Alternatives and Auxiliaries to Chemical Control Treatments” (J. Weintraub, unpublished data).     

The efficacy of eprinomectin extended-release injection against Hypoderma spp. (Diptera: Oestridae) in cattle

The efficacy of eprinomectin in an extended-release injection (ERI) formulation was determined in cattle harboring naturally acquired infestations of first- or second- and third-stage larvae of Hypoderma spp. in three studies conducted according to the same protocol in the USA (two studies) and Germany (one study). Thirty cattle sourced from herds with a history of Hypoderma infestation were included in each study. Cattle were formed into replicates of three animals each on the basis of pre-treatment anti-Hypoderma antibody titers. Within replicates each animal was randomly allocated to one of the following treatments: ERI vehicle (control) at 1 mL/50 kg bodyweight, administered once on Day 0; Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg), administered once on Day 0 (when larvae were expected to be first instars); or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg), administered once when larvae were second or third instars (study dependent, Day 73, 119, or 140). Treatments were administered by subcutaneous injection in front of the shoulder. In all studies, emerging and/or expressed Hypoderma larvae were recovered, speciated, and counted and viability was determined. Eprinomectin LAI treatment was 100% (p < 0.05) efficacious against first- and second- or third-stage larvae of Hypoderma bovis (two studies) and Hypoderma lineatum (one study). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.     

Eradication of Hypoderma species in Northern Ireland

The field measures for the control and eradication of the warble fly in Northern Ireland are described. The level of infestation and the main economic losses before the introduction of these measures are indicated. The limitations of the control measures used before the introduction of systematic insecticides are discussed.A limited field trial with a systematic insecticide was conducted in 1964, but the main national programme for warble control was implemented in 1966 and 1967. Under the programme, the treatment of all cattle was compulsory.The nature and organization of the programme and its staffing and cost are described. The field monitoring, the extent and nature of adverse reactions in some of the treated animals, the effects on the rate of warble infestation, and the current status of “warbles” as a Notifiable Disease are discussed. Also described is the practicality of the eradication of cattle grubs from the Island of Ireland as a whole through synchronization of the warble control programmes in Northern Irelabnd and Eire.     

The establishment and value of large,self-maintaining colonies of tsetse flies (glossina spp.)

Sumario Mención de la dificultad innata para cultivar moscas tse-tse (Glossina ssp.) en gran escala, es seguida por una breve descripción de los exitosos métodos elaborados en Langford, (Inglaterra) los resultados alcanzados, y el valor práctico de tales colonias para la investigación de trypanosomas y moscas tse-tse, y posiblemente para controlar el vector.

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L'établissement et valeur des larges colonies de mouches tsétsé soutient en soi.

Résumé Mention des difficultés inuees de l'élèvage en grand des mouches tsétsé est suivie par une histoire brève des methodes réussies developpées a Langford (Angleterre), les résultats achevés et la valeur pratique des telles colonies dans la récherche sur les trypanosomes et les mouches tsétsé et peutêtre dans le contr?le des vecteurs.

     

Possible induction in goats of immunological tolerance against the saliva of uninfected tsetse flies (Glossina spp.)

Summary Sensitization to the saliva of uninfected tsetse may occur in goats used for the maintenance of a tsetse fly colony. Data are given which suggest that this difficulty can be overcome if kids, from mothers used for fly feeding, are challenged with fly bites within 24 hours of birth and are thereafter subjected to a regular but slowly increasing fly challenge.

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Sumario La sensibilización contra la saliva de moscas tsetse no-infectadas, puede ocurrir en caprinos usados para el mantenimiento de una colonia de moscas tsetse. Se proporcionan datos que sugieren que esta dificultad puede ser vencida si los cabritos de madres usadas para la alimentación de las moscas, son desafiados con las mordidas de las moscas dentro de las 24 horas del nacimiento y son subsequentemente sometidos a un desafio regular pero creciente, con las mordeduras de estas moscas.

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Résumé La sensibilisation à la salive des glossines non infectées peut survenir chez les chèvres qui servent à nourrir les tsé-tsé entretenues en élevage. On rapporte ici des données qui suggèrent que cette difficulté peut être évitée si les chevreaux, issus des mères utilisées pour le gorgement des glossines, sont soumis aux piqures de celles-ci dans les 24 heures qui suivent la naissance et ensuite à une série régulière et lentement croissante de ces épreuves.

     

兔裸皮蝇对宿主高原鼠兔生理和个性特征的影响

以高原鼠兔(Ochotona curzoniae)为研究对象,比较感染与未感染兔裸皮蝇(Oestromyia lep-orina)的鼠兔生理特征(体重、束缚下的呼吸率和心率、体重矫正的静止代谢率、粪便皮质醇浓度)和个性特征(冒失性、温顺性、探索性)及其关联性.结果 表明:与未感染皮蝇的鼠兔相比,感染皮蝇的鼠兔体重、呼吸...     

Studies on the efficacy of deltamethrin applied to cattle for the control of tsetse flies (Glossina spp.) in southern Africa

Summary The tsetse fly (Glossina spp.) inhabits 11 million km² of Africa (Greekmore, 1989) where it is responsible for the transmission of trypanosomosis to man and animals. Because of its slow rate of reproduction, with females producing only four to five pupae per annum, control of the tsetse fly is the best means of controlling trypanosomosis. A number of different methods have been and are used but, whilst successes have been achieved, a long term solution has not been found.

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Resumen La mosca tsetsé (Glossina spp.) infesta 11 millones de km² (Greekmore, 1989) donde es responsable de la transmisión de tripanosomiasis al hombre y animales. Debido a la baja tasa de reproducción de la mosca (cuatro a cinco pupas por a?o), el control de la mosca per se es el método más efectivo, habiendose obtenido algún éxito, sin encontrer todavía una solución a largo plazo.

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Résumé La tsé-tsé (Glossina spp.) occupe 11 millions de km² du sol africain (Greekmore, 1989) et elle est responsable de la transmission de la trypanosomose chez l'homme et les animaux. En raison de son taux lent de reproduction (les femelles ne produisent que 4 à 5 larves par an) la luttre contre la tsétsé est la meilleure méthode pour combattre la trypanosomose. On a utilisé, et on utilise encore, de nombreuses techniques variées et bien que des succès aient été obtenus, aucune solution à long terme n'a encore été trouvée.

     

The ecological basis of parasite control: Ticks and flies

Tick and fly control programmes have undergone radical review in recent years. Insecticidal control measures are now often seen as a means of reducing target populations to a level sufficiently low for final eradication by biological or ecological techniques, the sterile male method (SIRM) being particularly favoured. As a preliminary, the new range of insecticidal application techniques includes insecticidal tags, bands, boluses, implants and pheromone baits. The final eradication programme could then involve the use of sterile flies or sterile hybrid ticks, for example. Immunization of cattle against ticks, the use of tick-resistant crossbreeds of cattle, tick-repellent grasses and dung burying beetles are among the additional techniques now being actively investigated.     

The potential impact of exotic Lymnaea spp. on fascioliasis in Australasia

The presence of the following exotic Lymnaea spp. has been recently confirmed in Australia: L. columella (North and South America, South Africa, New Zealand,) L. viridis (China, Japan, Philippines, New Guinea, Pacific Area), L. auricularia rubiginosa (Indochina, Malaysia, Indonesia) and L. peregra (Europe).In the present studies the relative susceptibility of the exotic snails noted above to Fasciola hepatica was investigated. Two of the species, L. columella and L. viridis, were found to be highly susceptible to the Australian strain of F. hepatica and a substantial number of viable metacercariae were produced. However a strong disparity in the host— parasite relationship was evident when the parthenogenetic development of the fluke in the two exotic snails was compared with that in the native L. tomentosa. It was concluded that L. tomentosa is a more suitable intermediate host for F. hepatica than any of the introduced exotic species, but it has to be considered that the host—parasite relationships between new combinations of Fasciola and Lymnaea spp. may improve by adaptation. In view of the results of the present studies the potential danger of fascioliasis spreading to areas currently not endemic in Australasia through introduced exotic snails is discussed with particular reference to Queensland, Western Australia and the Northern Territory.There is strong circumstantial evidence that the exotic snails were introduced with aquatic plants through the relatively free overseas and Australian trade. Similarly, through the introduction of infected snails, dangerous parasites such as F. gigantica of cattle and sheep or Schistosoma ssp. which cause serious diseases of man and animals could enter the subtropical or tropical regions of Australia. Appropriate State and Federal quarantine regulations are essential to prevent further introduction and spread of the snails, and monitoring of the distribution of established exotic snails in Australasia must be continuous.     

The biogeography of group sizes in humpback dolphins (Sousa spp.)

Humpback dolphins (Sousa spp.) are obligate shallow-water and resident species, and they typically live in fission–fusion societies composed of small-sized groups with changeable membership. However, we have scant knowledge of their behavioral ecology, starting with potential factors influencing inter-population variability of their group sizes. Here, we compiled a new global dataset of humpback dolphin group sizes based on 150 published records. Our data indicated an inter-specific consistency of group-living strategy among the 4 species in the Sousa genus, as these species preferred living in small-sized groups with a mean size of mostly no more than 10, a minimum size of single individual or small pairs, and a maximum size of several tens or ≈100. In addition, we clearly showed the geographic variations in group sizes of humpback dolphins at a global scale. We found that the geographic variations in humpback dolphin group sizes were primarily associated with the latitude, sea surface temperature, and abundance. To conclude, our findings provide insights into social dynamics and socioecological trade-offs of humpback dolphins, and help better understand how these resident animals adapted to their shallow-water habitats from the perspectives of biogeography and socioecology.     

Chemical composition of Eucalyptus spp. essential oils and their insecticidal effects on Lutzomyia longipalpis

The chemical composition of essential oils from three species of plants belonging to the Eucalyptus genus was determined and, their insecticidal effects on egg, larva and adult phases of Lutzomyia longipalpis were assessed. The insects were collected in the municipality of Sobral in the State of Ceará, Brazil. Five treatments with different concentrations were performed along with two negative controls, distilled water and Tween 80 (3%), and a positive control, cypermethrin (0.196 mg/ml). The tests were carried out in plastic pots internally coated with sterile plaster and filled with a substrate made of rabbit feces and crushed cassava leaves. The eggs, larvae and adults were sprayed with the oils. The hatched larvae were counted for 10 consecutive days and observed until pupation. Insect mortality was observed after 24, 48 and 72 h. E. staigeriana oil was the most effective on all three phases of the insect, followed by E. citriodora and E. globulus oils, respectively. The major constituents of the oils were Z-citral and alpha-citral (E. staigeriana), citronellal (E. citriodora) and 1,8-cineole (E. globulus). The Eucalyptus essential oils constitute alternative natural products for the control of L. longipalpis since the median effective concentration (EC₅₀) values revealed relevant action as compared with other natural products, some of their chemical constituents are already known for their insecticidal activity and these oils are produced in commercial scale in Brazil.     

Veterinary and public health aspects of Toxocara spp

Pet dogs and cats can play an important role in the transmission of zoonotic nematodes such as Toxocara canis and Toxocara cati, by excreting eggs directly into the human environment, without the involvement of vectors or intermediate hosts. Human toxocarosis remains a hazard despite the availability of highly effective anthelmintics for dogs and cats. A good understanding of the biology and epidemiology of these parasites, and the risk factors that lead to their transmission to humans is required for effective prevention strategies. In this respect, the maintenance of high quality continuing education for veterinarians and the provision of suitably presented information to pet owners are of priority importance. A closer collaboration between veterinary and public health professionals within the ‘One Health’ concept is also required.     

Phenotypic characterization of mastitic Prototheca spp. isolates

Bovine mastitis associated with Prototheca is considered a rare pathology, but is increasing in prevalence all over the world and therefore becoming more relevant to the dairy industry. The biochemical characterization of 47 Prototheca isolates retrieved from mastitic milk was performed in this study using API 20C Aux and two BBL Crystal Kits, followed by an analysis with InforBio software. The usage of this methodology, allowed the identification of discriminative phenotypic characteristics for the strains tested. The differential-character-finding algorithm used by this software permitted the identification of new phenotypic characteristics to discriminate between Prototheca zopfii, P. blaschkeae and P. wickerhamii, such as, citrate, phosphorycholine and arabinoside. The main objective of this study was to determine new phenotypic characteristics that allowed a better characterization of Prototheca spp. Usage of recent bioinformatic tools improved the analyses of several features that are important for a better characterization of Prototheca spp.     

The natural regulation of Trichostrongylus spp. populations in young grazing sheep

The dynamics of Trichostrongylus axei and intestinal Trichostrongylus spp. were studied in grazing lambs over a 2-year period. Monthly comparisons were made between worm counts of experimental lambs continuously exposed to infection from 3 to 7 months of age, and tracer lambs which were allowed to graze on the experimental plots for successive 4-week periods.It was found that irrespective of the level of larval intake, experimental lambs were unable to regulate their worm burdens until at least 5 months of age. When larval intake was high, resistance to establishment of larvae apparently occurred at approximately 6 months of age followed by rejection and resistance to reinfection. In conditions of low larval intake, worms accumulated with no apparent control operating in lambs up to 7 months of age.These results suggest that a rapid turnover of worm populations does not occur in Trichostrongylus spp., and that in young lambs, worms accumulate until sufficient exposure to infection stimulates resistance to larval establishment and ultimately rejection of adults.     

Babesia bigemina infection in yak (Poephagus grunniens L.): Molecular detection and characterization

Yaks contribute significantly in the Himalayan high land economy. Specific information on prevalence of babesiosis in yaks is lacking. A fast and reliable PCR assay targeting Babesia bigemina small subunit ribosomal RNA sequence (SS rRNA) was laboratory standardized for molecular detection of B. bigemina in yaks. Restriction digestion of the PCR amplified 675 bp target sequence with Vsp I confirmed the prevalent species of Babesia as B. bigemina. Nucleotide sequencing and phylogenetic analysis of PCR amplified 675 bp SS rRNA sequence revealed a close genetic relationship with other bovine isolates of B. bigemina. A PCR based survey involving 94 blood samples of yak from the National Research Centre on Yak, Dirang, Arunachal Pradesh detected infection in 5.32% of yak blood samples, which was significantly higher in comparison to microscope based detection of infection in 2.13% blood smears. This is the first report on sensitive PCR based detection of B. bigemina infection in yaks and PCR-RFLP and nucleotide sequence analysis based molecular characterization of the B. bigemina isolated from yaks.     

Occurrence of Mycobacterium spp. and other pathogens in lymph nodes of slaughtered swine and wild boars (Sus scrofa)

Mycobacterium spp. and other pathogens were investigated in 258 swine lymph nodes (129 with and 129 without apparent lesions), and 120 lymph nodes (60 with and 60 without lesions) from wild boars (Sus scrofa). A total of lymph nodes from swine and wild boars were collected of different animals. Submaxillar and mesenteric lymph nodes were submitted to microbiological examination and colonies suggestive of Mycobacterium spp. (alcohol-acid bacilli) were submitted to PCR Restriction Assay (PRA). In swine with lymphadenitis, Mycobacterium spp. (24.1%) and Rhodococcus equi (13.2%) were the most prevalent microorganisms, while in lymph nodes without lesions were identified a complex of microorganisms, including of environmental mycobacteria. In wild boars with lymphadenitis, ß-haemolytic Streptococcus (10.0%), Mycobacterium spp (8.4%) and R. equi (6.6%) were the most frequent. Among mycobacterias were identified predominantly Mycobacterium avium subspecies type 1 (48.3%) and M. avium subspecies type 2 (16.1%), followed by Mycobacterium intracellulare, Mycobacterium szulgai,Mycobacterium fortuitum, Mycobacterium gordonae, Mycobacterium simiae, Mycobacterium nonchromogenicum and Mycobacterium intracellulare type 2.     

Prevalence and antimicrobial susceptibility of Salmonella spp. in small Indian mongooses (Herpestes auropunctatus) in Grenada,West Indies

Intestinal samples from 156 small Indian mongooses (Herpestes auropunctatus) collected island-wide in Grenada from April 2011 to March 2013 were examined for the presence of Salmonella enterica spp. Nineteen (12%) mongooses were culture-positive for S. enterica spp. of which five serotypes were identified. Salmonella javiana and S. Montevideo were the most commonly isolated serotypes. The other serotypes isolated were S. Rubislaw, S. Panama and S. Arechavaleta. All isolates were susceptible to amoxicillin–clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, imipenem and trimethoprim–sulfamethoxazole. One isolate (S. Montevideo) showed resistance to tetracycline and intermediate resistance to streptomycin. The five isolated Salmonella serotypes are potential human pathogens suggesting that the mongoose may play a role in the epidemiology of human salmonellosis in Grenada.