Haemonchus in India

Scientometric Analysis of Gastrointestinal Parasites Prevalence in Sheep and Goats of India

PURPOSE

In the present study, gastrointestinal parasites (GIP) prevalence in sheep and goats from India was estimated by scientometrics.

METHODS

The GIP prevalence studies (86) reported during 1998-2021 was obtained from online databases, and offline literatures, meta-analysis was undertaken by using "meta" package in R-Software.

RESULTS

The pooled GIP prevalence in India was 65% (95% level CI 56-74%, PI 12-96%) in sheep, 74% (95% level CI 66-80%, PI 14-98%) in goats and 68% (95% level CI 62-73%, PI 15-96%) in sheep and goats. Period-wise analysis revealed a higher GIP prevalence during 1998-2010 than the recent periods. Among the zones, GIP prevalence was higher in the Central zone (79%) in sheep, North zone (82%) in goats, and Central zone (78%) in sheep and goats. Based on the state-wise analysis, a higher GIP prevalence was observed in Haryana for sheep, Himachal Pradesh for goats, and Uttarakhand for sheep and goats. In India, a higher prevalence was reported by nematodes than other parasite classes. Based on climatic regions, a higher GIP prevalence was observed in semi-arid Steppe type region (84%).

CONCLUSION

The high prevalence zones, states, species, sample types, parasite classes, parasite species and climate regions of GIP will be useful in decision-making and resource use efficiency by policymakers and stake holders. There is an urgent need to prevent the occurrence of GIP infections in sheep and goats by adopting scientific management practices, effective therapeutic measures, and hygienic practices on farms to augment the economic benefits to sheep and goat farmers in India.

Influence of intensive rearing, continuous and rotational grazing systems of management on parasitic load of lambs

AIM

A trial was conducted to assess the influence of parasitic load on the lambs reared under the intensive system, continuous grazing, and rotational grazing systems of management.

MATERIALS AND METHODS

A total of thirty numbers of the undetermined breed of ewe lambs around 4-5 months of age were randomly selected and allotted to three treatment groups: T1 (intensive system - control), T2 (rotational grazing), and T3 (continuous grazing). The T1 group lambs were raised under a stall-fed system of management, the T2 group lambs were grazed under rotational grazing strategy in four paddocks of plot-A, while the T3 group lambs were continuously grazed in plot-B.

RESULTS

At the end of the study, there was a highly significant difference (p=0.01) in the fortnightly strongyle egg count per gram (EPG) of feces among the lambs pertaining to the three treatment groups; the lambs in T3 had a higher strongyle EPG compared to T2 lambs. With regard to the overall reduction in EPG from the initial count, lambs under rotational grazing showed the maximum decrease of 54.52% compared to lambs under T3 (continuous grazing). There was a strong positive correlation noticed between the mean temperature of the day at each fortnight and the subsequent EPG at each fortnight with R2=0.87. There was a strong positive correlation noticed between mean FAMACHA© scores and the EPG with R2=0.84, R2=0.83, and R2=0.83 for T1, T2, and T3, respectively.

CONCLUSION

The grazing management with pasture rotation should be considered as a viable option for sustainable parasitic control in case of grazing-dependent livestock husbandry in India.

Behavioural and productive response to experimental infection with stage 3 larvae of Haemonchus contortus in feedlot bull-calves

Haemonchus contortus is a nematode parasite that establishes in the abomasum of ruminants, it has a cosmopolitan distribution and is a worldwide health problem for livestock. As a first line of defence against parasites, behaviour can help to prevent or fight infection, and may even serve as a method of early presumptive diagnosis. Parasites can affect performance of cattle and cause significant economic losses. The aim of this study was to determine the behavioural and productive changes induced by an experimental infection with H. contortus L3 in bovines. We used 32 dewormed bull calves, randomly divided into two groups, 8 no inoculated controls and 24 that were inoculated with 4000 L3 of H. contortus. Inoculation did not influence haematocrit or haemoglobin values at 0, 28 and 42 days post infection (P> 0.20); however, an increase in the frequency of urination (P = 0.0001) and defecation (P = 0.0001), number of steps (P < 0.001) and self-grooming (P < 0.01) events were observed, even in inoculated animals in which not parasite eggs were found in faeces. During the first 28 days post-inoculation with H. contortus, feedlot performance was not affected (P = 0.16), but during the last 14 days (29-42) inoculated animals gained 15% less weight compared to controls (P = 0.04). Over 42 days, inoculated calves showed a 28% poorer feed efficiency during the 42 days post-inoculation than controls (P < 0.01). Across the experiment, calves inoculated with H. contortus obtained less net energy both for maintenance as for gain from diet (P < 0.01). It is concluded that both, performance and behaviour were modified in feedlot bull-calves parasitized by H. contortus, supporting the practice of deworming when eggs of this parasite are detected in the faeces even in low amounts.

Polymerase chain reaction (PCR) based amplification of hmcp3 and hmcp6 cysteine protease genes of Haemonchus contortus from small ruminants

Haemonchus contortus is a haematophagous nematode in small ruminants population and causes anaemia, weakness and mortality especially in young animals. In the present study, hmcp3 partial gene of 836 bp and hmcp6 full length gene of 1041 bp were amplified from the cDNA of Bareilly isolate of adult male H. contortus by polymerase chain reaction. Further gene characterization and expression studies are warranted to know the immunoprophylactic potential of hmcp3 and hmcp6 proteins of H. contortus.

Prevalence of intestinal and haemoprotozoan parasites of small ruminants in Tamil Nadu, India

Aim:

The aim of the present study is to assess the prevalence of intestinal and haemoprotozoan parasites of small ruminants (Sheep and Goats) in North Western part of Tamil Nadu, India.

Materials and Methods:

A total of 630 faecal samples (251-sheep, 379-goats) and 554 blood smears (242-sheep, 312-goats) were examined, for the presence of eggs of intestinal and haemoprotozoan parasites, respectively. The samples were received from the Veterinary college hospital and Veterinary dispensaries in North Western part of Tamil Nadu. Faecal samples were processed by sedimentation technique and examined under low power objective (×10), and blood smears were stained using Giemsa’s technique and examined under oil immersion (×100).

Result:

The analysis of data on the prevalence of intestinal and haemoprotozoan parasites of sheep and goats in North Western part of Tamil Nadu for the period from 2004 to 2013, showed an overall prevalence of intestinal parasites was found to be 67% and 35% in sheep and goats, respectively, whereas only 11% of sheep and 3% of goats had the haemoprotozoan parasitic infection. Highly, significant difference (p<0.01) in the prevalence of intestinal (χ²=65), and hemoprotozoan (χ²=15.4) parasitism was observed between sheep and goats. Intestinal parasites such as strongyles, Trichuris, Moniezia, amphistome, and coccidia were identified in which the highest prevalence was observed with coccidia, followed by strongyles, Monezia, Trichuris, and least with amphistome in both the sheep and goats. The haemoprotozoan parasites recorded were Theileria and Anaplasma species, of which, Anaplasma spp. being the highest and Theileria spp. the least prevalent in both the sheep and goats. The seasonal prevalence of intestinal parasites showed highest in rainy season, followed by moderate in winter and least with summer in both the sheep and goats, whereas the haemoprotozoan parasites recorded were the highest in summer followed by winter and least with rainy season.

Conclusion:

The present study suggests that North Western part of Tamil Nadu is highly endemic for intestinal parasites such as coccidia and strongyles and haemoprotozoans such as Anaplasma and Theileria species in small ruminants.

Cysteine proteinase genes in Indian strain of Haemonchus contortus

The genes of microvillar cysteine proteinases such as hmcp1, hmcp6 and gcp7 of phenotypically distinct morphotypes of female H. contortus having knobbed and linguiform vulvar flaps were cloned and characterized. Complementary DNA (cDNA) was synthesized from total RNA of both the morphotypes. The hmcp1, hmcp6 and gcp7 genes were amplified from cDNA. The amplicons were cloned in pDRIVE T/A cloning vector and sequenced by Sanger's dideoxy method. The nucleotide and deduced amino acid sequences were compared with the USA/UK strain H. contortus cysteine proteinase sequences. The cysteine proteinase genes of Indian strain show considerable variations with USA/UK strains. Our results revealed that Indian strain of H. contortus expresses both UK strain (hmcp1 and 6) and USA strain (gcp7) cysteine proteinases.

Glyceraldehyde-3-phosphate dehydrogenase of the parasitic nematode Haemonchus contortus binds to complement C3 and inhibits its activity

Haemonchus contortus is an economically important gastrointestinal parasite that infects primarily sheep and goats. To survive inside the host, the parasite must overcome the host immune response. In this study, we have identified and characterized a complement-C3-binding protein (H.c-C3BP) from this parasite employing biochemical and molecular biology tools. Initially, a truncated form of the protein was isolated from the excretory-secretory products of the parasite using C3-Sepharose column that facilitated its identification by mass spectroscopy. Subsequently, the parent molecule was generated in E. coli, and sequence analysis confirmed it as glyceraldehyde-3-phosphate dehydrogenase (GAPDH). GAPDH reacted with the antiserum raised against the truncated protein, and the truncated protein reacted with anti-GAPDH antiserum. The protein inhibited complement function as measured by haemolytic assay and membrane attack complex (MAC) formation. Sera from H. contortus-infected animals reacted with GAPDH as well as the truncated form of the protein, which further lend support to protein secretion. Thus, the C3-binding property of H. contortus GAPDH is a new function, and it represents a new entity of complement-binding protein. Identification and characterization of H.c-C3BP should facilitate development of new therapeutics considering a key role of this protein in immune modulation.

Characterization of Haemonchus contortus calreticulin suggests its role in feeding and immune evasion by the parasite

Haemonchus contortus, a gastrointestinal parasite of sheep and goat feeds on the blood of its host and causes bleeding at the biting site. In this report, we demonstrate that the Ca2+ binding protein, calreticulin (CalR), is present in excretory/secretory products of adult worms. The secreted CalR enhanced plasma coagulation time. Using recombinant fragments, this property has been mapped to C-terminal part of the molecule which has binding sites for Ca2+ as well as clotting factors. Complement protein C1q bound to immobilized CalR and C1q dependent lysis of sensitized sheep erythrocytes was inhibited by CalR, a function mapped to N-domain of the protein. Factor X and a 24 kDa polypeptide derived from prothrombin but not prothrombin bound to immobilized CalR. The binding site for 24 kDa polypeptide in the CalR molecule has been localized in the P-domain. Our results suggest at least two functions for secreted CalR: first, to prevent blood clotting by binding to Ca2+ and clotting factors thus enabling parasite to feed on the host blood and second to modulate the host immune response by binding to complement C1q thereby facilitating parasite's survival within the host.

Susceptibility of two crossbreeds of sheep to Haemonchus contortus

Studies were conducted on 20 crossbred lambs of 4-5 months old. Ten lambs were Nali x Corriedale cross (Hisardale) and the other 10 were Nali x Lohi cross (Munjal). Seven lambs each of both crossbreeds were infected with 10,000 infective larvae of Haemonchus contortus. Three lambs of each crossbreed served as uninfected controls. Clinicopathological examinations were done before and after infection and all the lambs were necropsied 28 days post-infection. The body weight gain, haemoglobin and packed cell volume were significantly lower in Hisardale lambs and the peripheral eosinophil count was significantly higher in Munjal lambs. Significant hypoalbuminaemia and hypoglobulinaemia, a sharp increase in albumin: globulin ratio; significantly higher faecal egg counts; adult worm counts; abomasal pH, volume, congestion and oedema were observed in Hisardale lambs as compared to Munjal lambs. Clinical signs of haemonchosis were more severe in Hisardale lambs and two of them died. Munjal lambs therefore seem less susceptible than Hisardale lambs to H. contortus infection.

Changes in liveweight gain, blood constituents and worm egg output in goats artificially infected with a sheep-derived strain of Haemonchus contortus

Two groups of goats were dosed with 10,000 and 20,000 sheep-derived strain (SDS) larvae of Haemonchus contortus respectively. Over a period of 42 days goats dosed with 20,000 larvae lost more weight than those dosed with 10,000 larvae. Infected goats showed anaemia from about 2 weeks after infection as well as reduced levels of total serum proteins and albumins.

Effects of anthelmintics on Haemonchus contortus (Nematoda: Trichostrongylidae)

The review summarizes and evaluates recent information about the effects of anthelmintics on Haemonchus contortus. The topic is discussed under the headings effects of drugs on the absorptive surfaces, effects of drugs on metabolism, effects of drugs on the neuromuscular system, effects of drugs on developmental stages, anthelmintic efficacy, and resistant strains. Possible future lines of work are suggested in the conclusions.