A critical role for thermosensation in host seeking by skin-penetrating nematodes.

Infection with gastrointestinal parasitic nematodes is a major cause of chronic morbidity and economic burden around the world, particularly in low-resource settings. Some parasitic nematode species, including the human-parasitic threadworm Strongyloides stercoralis and human-parasitic hookworms in the genera Ancylostoma and Necator, feature a soil-dwelling infective larval stage that seeks out hosts for infection using a variety of host-emitted sensory cues. Here, we review our current understanding of the behavioral responses of soil-dwelling infective larvae to host-emitted sensory cues, and the molecular and cellular mechanisms that mediate these responses. We also discuss the development of methods for transgenesis and CRISPR/Cas9-mediated targeted mutagenesis in Strongyloides stercoralis and the closely related rat parasite Strongyloides ratti. These methods have established S. stercoralis and S. ratti as genetic model systems for gastrointestinal parasitic nematodes and are enabling more detailed investigations into the neural mechanisms that underlie the sensory-driven behaviors of this medically and economically important class of parasites.

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Terror in the dirt: Sensory determinants of host seeking in soil-transmitted mammalian-parasitic nematodes

Prevalence and risk factors associated with gastrointestinal parasites in ruminant livestock in the Coastal Savannah zone of Ghana.

Gastrointestinal parasites are the main cause of losses of cattle farms including feed conversion-failure and even death of heavily infected animals. We have conducted a random examination of 455 cows in the Special Region of Yogyakarta-Central Java from March to June 2016. The examined animals were Ongole and Local Cattle (PO) cross breed, Simmental breed, Limousin breed, Simmental and PO cross breed, PO and Limousin cross breed, Friesian Holstein breed (FH), Brahman breed, Angus breed, Angus and Brahman cross breed and Bali breed. McMaster technique, saturated NaCl flotation technique and Parfitt and Banks technique were used simultaneously in this study in order to identify the parasitic stages present in the coprological samples. The test results showed that approximately 65.93% of the cattle population was infected by parasitic stages, such as: Strongylidae (54.00%), Fasciola sp. (17.00%), Eimeria spp. (15.33%), Strongyloides sp. (4.67%), Paramphistomum sp. (4.00%), Trichuris sp. (3.67%) and Moniezia sp. (1.33%). Six different Eimeria species were identified: E. bovis, E. auburnensis, E. bukidnonensis, E. canadaensis, E. zurnii and E. cylindrica. Most of the animals presented monoinfections (79.33%), but concomitant infections were also observed (2 different parasites: 17.67%; 3 different parasites: 2.33%; more than 3 different parasites: 0.67%). With this work we proved the high level of parasitism in cattle of Central Java and we intensively highlight the need to find adequate control measures against parasitic diseases in order to reduce the detrimental impact of parasitosis in cattle.

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Gastrointestinal Parasites of Cattle in Central Java

An approach to preventing strongyle infection in horses was tested, comprising rotational pasturing and the administration of spores of two parasiticidal fungi, Mucor circinelloides and Duddingtonia flagrans. Twenty-two adult Spanish Sport Horses were dewormed with ivermectin (1 mg pour-on/kg body weight) and then randomly divided into three groups. G-1 was maintained with continuous grazing, and G-2 and G-3 were kept on a four-paddock rotation system. Commercial pelleted feed (2.5 kg/horse) was supplied to G-1 and G-2 twice a week; horses in G-3 received pellets containing 2 × 106 spores/kg of each fungus. Fecal samples were analyzed by the flotation method to estimate the reduction in the fecal egg counts (FECR), the percentage of horses shedding eggs (PHR), and the egg reappearance period (ERP). Third-stage larvae were identified in fecal pats as Cyathostomum (sensu lato) types A, C and D, Gyalocephalus capitatus, Triodontophorus serratus, Poteriosthomum spp., Strongylus vulgaris and S. edentatus. Two weeks after treatment, the FECR values were 100% in G-1, 96% in G-2 and 99% in G-3; the PHR values were 100% in G-1, 75% in G-2 and 88% in G-3. A strongyle ERP of 6 weeks was observed in G-1, ERP of 10 weeks was observed in G-2, and ERP of 16 weeks was observed in G-3. The counts of eggs per gram of feces (EPG) were > 300 EPG in G-1 and G-2 but remained below 250 EPG in G-3 throughout the observation period of 12 months. These results suggest that horse strongyle infection could be decreased by combining rotational pasturing with feeding pellets containing the spores of parasiticidal fungi.

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A combined effort to avoid strongyle infection in horses in an oceanic climate region: rotational grazing and parasiticidal fungi

It is a challenging task to control internal parasites in grazing livestock even by applying multi label and multi directional approach. It is impossible to draw general recommendations to control parasitic diseases due to varied geo-climatic conditions and methods adopted for rearing the livestock in the country like India. In view of increasing incidence of anti-parasitic drug resistance in animals, there is an urgent need to design sustainable parasite control strategy which must include on the host as well as off the host control measures to harvest the maximum productivity from the animal for an indefinite period.

Veer Singh Rathor

Papers

Internal parasite management in grazing livestock