Echinococcus Granulosus In Sheep Research Articles

Determination genetic variation and phylogenetic analysis in Echinococcus granulosus isolated from Iraqi sheep

Echinococcus granulosus causes Cystic Echinococcosis disease in intermediate hosts, such as sheep, cattle, goats, camels, and horses. Cystic Echinococcosis is an essential parasitic zoonosis that affects humans and animals and is a significant public health and economic problem worldwide. This study aimed to determine the molecular characterization and phylogenetic analysis of Echinococcus granulosus in sheep's livers and lungs. The genetic variation was performed by directly sequencing the mitochondrial DNA (mtDNA) genes coding of the NADH dehydrogenase subunit 1 (ND1). The evidence from molecular studies and DNA sequencing revealed that the Isolates of Echinococcus granulosus in Kirkuk city related to the sheep strain G1 genotype. The alignment analysis showed a concordance between isolates with each other by 99%. When comparing the results with Genbank, it indicated the occurrence of genetic variations between nucleotides represented by eleven codons, seven of which represent transversion mutations, and four are transition mutations.

Epidemiology and spatial distribution of Echinococcus granulosus in sheep and goats slaughtered in a hyperendemic European Mediterranean area

BackgroundCystic echinococcosis (CE) is a worldwide parasitic zoonosis caused by the larval stage of Echinococcus granulosus sensu lato affecting livestock, particularly sheep and goats. However, often this parasitosis is underestimated. For this reason, this study aimed to evaluate the epidemiological features and spatial distribution of CE in sheep and goats slaughtered in a hyperendemic Mediterranean area.MethodsA survey was conducted in the Basilicata region (southern Italy) from 2014 to 2019. A total of 1454 animals (1265 sheep and 189 goats) from 824 farms were examined for hydatid cyst detection by visual inspection, palpation and incision of target organs. All the CE cysts were counted and classified into five morphostructural types (unilocular, multiseptate, calcified, caseous and hyperlaminated). Molecular analysis was performed on 353 cysts. For spatial analysis, a kriging interpolation method was used to create risk maps, while clustering was assessed by Moran’s I test.ResultsCE prevalence of 72.2% (595/824) and 58.4% (849/1454) was observed at the farm and animal levels, respectively, with higher values in sheep (62.9%) than goats (28.0%). The liver and lungs were the most frequently infected organs in both sheep and goats. Most of recovered cysts were of the calcified and multiseptate morphotypes. All the isolates were identified as E. granulosus sensu stricto (genotypes G1–G3). Spatial distribution showed a moderate clustering of positive animals.ConclusionThe findings of this study can be used to better understand the eco-epidemiology of echinococcosis and to improve CE surveillance and prevention programs in regions highly endemic for CE.Graphical abstract

Cystic echinococcosis: an emerging zoonosis in southern regions of Khyber Pakhtunkhwa, Pakistan

BackgroundCystic echinococcosis (CE) is one of the principal causes of economic loss to the livestock industry because of its morbidity and mortality of food-producing animals and condemnation of important visceral organs. Pakistan being an agricultural country having an extensive livestock sector, is mostly practiced by poor people, which has a fundamental role in the economy. The present study was aimed to conduct a cross-sectional survey and PCR based confirmation of Echinococcus granulosus in sheep, goats, cows, and buffaloes from southern regions (three districts: Lakki Marwat, Bannu, and Karak) of Khyber Pakhtunkhwa, Pakistan. During the study, a total of 2833 animals were examined randomly including; sheep (n = 529), goats (n = 428), cows (n = 1693), and buffaloes (n = 183). Hydatid cysts were collected and examined for the presence of protoscoleces using microscopy. Detection of DNA was performed by using PCR and two mitochondrial genetic markers namely; NAD-1 and COX-1 were amplified.ResultsThe overall prevalence of CE was found to be (9%) among the examined animals. The hydatid cyst infection was highly prevalent in buffaloes (12%), followed by sheep (10%), cows (9%), and goats (5.1%). Cystic echinococcosis was more prevalent (10%; 96/992) in district Lakki Marwat followed by district Bannu (9%; 112/1246) and Karak (7%; 39/595). Female animals were more likely to be infected with CE (11.6%) than male animals (5.3%) (p = 0.001). Similarly, the infection was higher in the older group of animals as compared to younger (p = 0.001). Mostly (52.2%; n = 129) of hydatid cysts were found in the liver, while (64.4%; n = 159) cysts of the infected animals were infertile. PCR based identification confirmed the presence of E. granulosus sensu stricto (s.s) in the study area.ConclusionCystic echinococcosis was found to be highly prevalent in southern regions of Khyber Pakhtunkhwa and could be a potential threat to human health. Moreover, molecular sequencing and phylogenetic analyses should be carried out in future to identify the prevailing genotype (s) of E. granulosus s.s.

Epidemiological study of Echinococcus granulosus in sheep in the Gharb plain (North-West of Morocco).

Hydatidosis is considered endemic in Morocco and caused serious health problems in ruminants. The aim of this research is to present an epidemiological study on echinococcosis in sheep. The study was carried out between April 2016 and May 2017. A total number of 1600 sheeps was examined via autopsy for Echinococcus granulosus in various slaughterhouses in the Gharb plain of Morocco. The Results of the study showed that the prevalence of cystic echinococcosis was 7.63%. The infection was not significant among sheep which age is < 1 year (2.67%), while it increases among those which age is from 1 to 3years old (8.63%). It also grows significantly among sheep which age is over 3years old (11.71%). Parasitized at 62%, the liver is the most affected organ followed by the lungs (38%). Protoscoleces are only found in liquid cysts and contribute to their fertility which is estimated at 66.66% in the liver and 57.74% in the lungs. In addition, the prevalence of calcified cysts is 12.24% in the liver and 21.11% in the lungs. Examination of the fertile cysts revealed a high level of Protoscoleces viability, whether it's in the liver (65.93%) or in the lungs (59.30%). This study also shows how the evolution of echinococcosis is closely linked to sex and age.

Prevalence and genotyping of Echinococcus granulosus in sheep in Narok County, Kenya.

Cystic echinococcosis (CE) is a zoonotic disease caused by the larval stage of Echinococcus granulosus species (sensu lato, s.l.). In East Africa, several species/strains occur in livestock, wildlife, and humans, but there is limited information on frequencies of infection by different genotypes in the various mammalian hosts. We have obtained data on E. granulosus infection prevalence in sheep sampled from abattoirs in Narok County, southern Kenya. We inspected carcasses for the presence of hydatid cysts in 180 sheep randomly selected in five sub-locations. The overall prevalence was 16.0% (144/900 animals), with the majority of cysts (50.7%) found in the liver, followed by the lungs (36.8%), while infections involving the liver and lungs were detected in 12.5% of the sheep. PCR-RFLP genotyping of the mitochondrial nad-1 gene in all the 343 cysts identified E. granulosus G1-G3 (sensu stricto, s.s.) as the only genotype. The majority of the cysts (62.1%) were fertile, and 35.2% were sterile, while 2.7% were calcified. Considering cyst fertility, 73.02% of lung cysts were fertile compared to 53.4% in liver cysts. Our data extends previous CE studies in livestock and indicates a high level of CE infection of sheep in Narok, with a predominance of E. granulosus s.s., which is highly pathogenic and commonly infects humans. Given the high fertility rates observed in the cysts, there is an urgent need to determine whether there is a significant incidence of human infection in Narok, and initiate "One Health" control measures.

Immunization of sheep against Echinococcus granulosus with protoscolex tegumental surface antigens.

Aim:Cystic echinococcosis (CE) has potential economic effects to both animal products and human health. A vaccine to protect livestock against CE can be effective in reducing economic costs and increasing the livestock products. Protoscolex tegumental surface antigens (PSTSA) used to induce the production of specific antibodies against Echinococcus granulosus in sheep. The tegumental antigens were extracted from viable protoscolices by solubilization in sterile phosphate-buffered saline containing decanoyl-N-methylglucamine.Materials and Methods:Ten lambs which were infected with CE (positive control), 10 negative control, and 10 test groups of sheep were included in the study. 300 µg emulsion of purified-PSTSA was injected intramuscularly in a two-step immunization on the first and 30 days. Sera were collected immediately before immunization and 6 times with 10-day intervals until 60 days post immunization. Thereafter, the sera were tested for antibodies by indirect hemagglutination test in microtiter plate.Results:After two immunizations, all the infected animals in test group showed substantial increases in antibody titer. Statistical analysis showed a significant difference between the titer obtained in the test and negative control groups in both phases of immunization (p<0.05).Conclusion:The results showed that the PSTSA is a promising immunogenic compound for immunization of sheep against CE.

Development of a colloidal gold immunochromatographic strip based on HSP70 for the rapid detection of Echinococcus granulosus in sheep

Echinococcus granulosus is the causative pathogen of cystic echinococcosis, a serious disease endangering human and animal health. In this study, an immunochromatographic strip was developed based on the recombinant protein Heat shock protein 70 (HSP70) for the serological detection of E. granulosus. The protocol completes within 20min requiring no specialized equipment or chemical reagents, while specificity tests confirmed no cross-reactivity with positive serum of Fasciola hepatica, Haemonchus contortus, Peste des petits ruminants virus (PPRV) and Foot-and-mouth disease virus (FMDV). The strips remained stable after storage at 4°C for up to 8 months. Both immunochromatographic strip and ELISA tests were applied to detect E. granulosus antibody in a total of 728 serum samples obtained from slaughter houses in Zhejiang Province. Our data revealed positive rates of 2.61 and 1.65% by immunochromatographic strip and ELISA methods, respectively. The immunochromatographic strip test developed in this study provides a simple, specific and rapid method of E. granulosus antibody detection and infected sheep monitoring.

Immunoprotection of recombinant Eg.P29 against Echinococcus granulosus in sheep.

ObjectiveThis study aims to investigate the immunoprotection of recombinant Eg.P29 (rEg.P29) vaccine and analyze the underlying mechanism in sheep.MethodsThree groups of male sheep were immunized subcutaneously with rEg.P29 and PBS, Freund’s complete adjuvant as controls, respectively. After prime-boost vaccination, the sheep were challenged with encapsulated Echinococcus granulosus eggs. The percentage of protection in sheep was determined 36 weeks after the infection. Humoral immune response was analyzed for specific IgG, IgG1, IgG2, IgM and IgE levels. Moreover, cytokines including interferon (IFN)-γ, interleukin (IL)-2, IL-4,and IL-10 were also evaluated.ResultsImmunization with rEg.P29 induced protective immune responses up to 94.5 %, compared with immunoadjuvant group. The levels of specific IgG, IgG1, IgG2, and IgE as well as IFN-γ, IL-2, and IL-4 significantly increased after two immunizations (P < 0.05); however, the levels of IgM and IL-10 did not show difference.ConclusionrEg.P29 showed Immunoprotection and induced Th1 and Th2 immune responses; hence, rEg.P29 is a potential vaccine for E. granulosus infection.

Serological monitoring of protection of sheep against Echinococcus granulosus induced by the EG95 vaccine

Although immunity to Echinococcus granulosus in sheep has been shown to be antibody-mediated and complement-dependent and can be passively transferred in colostrum, in animals vaccinated with EG95, the relationship between protection against an oral challenge infection with E. granulosus eggs and anti-EG95 IgG ELISA absorbance values at the time of challenge has not been satisfactorily proven. Using a combination of results from three EG95 vaccination trials, we have found that the IgG ELISA absorbance at the time of challenge infection explains approximately 50% (P ≤ 0·001) of the variability in the percentage protection against an oral challenge with E. granulosus eggs (transformed with arcsin).

Molecular characterization of Echinococcus granulosus in sheep and goats of Peloponnesus, Greece

Although cystic echinococcosis (CE) has been a recognized public health problem in Greece, molecular data are lacking regarding the types and prevalences of infecting strains of the etiological agent Echinococcus granulosus. Therefore, we investigated the prevalence of CE and determined the infecting genotypes in sheep and goats in Peloponnesus, a large region of southern Greece. Liver and lung samples were obtained from 210 sheep and 190 goats slaughtered between January and December 2005, and the number, morphology, and fertility of hydatid cysts were determined. Protoscoleces or germinal layers were collected from individual cysts (20 sheep and 20 goats), and DNA was extracted. A polymerase chain reaction (PCR)/seminested PCR system was used to distinguish the G1, G5, and G6/G7 strains, and a specific molecular diagnosis was obtained by sequencing PCR-amplified mitochondrial DNA encoding cytochrome c oxidase subunit 1 and NADH dehydrogenase I genes. The prevalence of CE was 30.4% in sheep and 14.7% in goats; fertile cysts were found in 16.2 and 7.4%, respectively. Overall, 18 of 20 sheep harbored the G1 genotype (common sheep strain), while the remaining two animals had the G3 (buffalo) strain. All 20 goats were infected with the G7 (pig) strain. These results document the prevalence of E. granulosus infection in food animals in this geographical area and reveal for the first time the presence of, at least, three parasite genotypes.

Modelling the transmission dynamics of Echinococcus granulosus in sheep and cattle in Kazakhstan

Cystic echinococcosis, caused by Echinococcus granulosus, is an emerging disease in many parts of the world and, in particular, in eastern Europe and the former Soviet Union. This paper examines the abundance and prevalence of infection of E. granulosus in cattle and sheep in Kazakhstan. Observed data are fitted to a mathematical model in order to determine if the parasite population is partly regulated by intermediate host immunity and to define parameters in the model. Such data would be useful to develop simulation models for the control of this disease. Maximum likelihood techniques were used to define the parameters and their confidence limits in the model and the negative binomial distribution was used to define the error variance in the observed data. The results indicated that there are significant variations in the infection pressure to sheep depending on their location. In particular sheep from Almaty Oblast and from central and northern Kazakhstan appeared to have a greater exposure than sheep from Jambyl or South Kazakhstan Oblasts. The infection pressure to cattle was somewhat lower in comparison. In common with other similar studies, there was no evidence of parasite-induced immunity in sheep or cattle in Kazakhstan due to natural infection. The highest abundance and prevalence were seen in the oldest age classes of animals.

Assessment of protective immune responses against hydatid disease in sheep by immunization with synthetic peptide antigens

Four synthetic peptides which comprise the immunodominant linear epitopes of the EG95 recombinant protein, were investigated for their ability to induce host-protective immunity against Echinococcus granulosus in sheep. Sheep were immunized with either free peptide or peptide conjugated to diphtheria toxoid and challenge infected with E. granulosus eggs. All of the peptides elicited specific antibody, but these did not kill the parasite in in vitro culture assays, nor did the peptides induce protection against challenge infection. In contrast, anti-EG95 antibodies affinity purified against each of the 4 peptides were lethal to the parasite in in vitro culture. These affinity-purified antibodies were shown to contain specific antibody to both peptide and EG95. In in vitro inhibition assays, the peptides did not diminish anti-EG95 antibody binding to EG95 or parasite lysis in oncosphere killing assays. These results suggest that the fine specificities of antibodies raised against the recombinant protein are different to those raised against the peptide immunogens and that the majority of the antibody induced by vaccination with EG95 is raised against conformational determinants.

Echinococcus granulosus in sheep: Transfer from ewe to lamb of ‘Arc 5’ antibodies and oncosphere-killing activity, but not protection

Fourteen ewes were orally dosed with 2000 E. granulosus eggs at 2 weeks of age, were mated at 19 months, and produced lambs when the cysts were 2 years old. One week after parturition, all 14 ewes had ‘Arc 5’ antibodies in their serum, as did 11 14 of their lambs. Fourteen uninfected ewes were immunized three times before parturition with E. granulosus eggs injected intramuscularly. Cysts grew at the first, or first and second site, but not the third, indicating that the ewes were immune prior to parturition. Most sera from these ewes and their lambs, and from 14 control ewes and their lambs, produced precipitin arcs with hydatid cyst fluid, but no ‘Arc 5’. All lambs were challenged with 500 eggs 2 weeks after birth. At necropsy, cyst numbers within groups ranged from 3 to > 200, but there was no significant difference between the three groups of lambs. The immunized ewes did not pass a protection to their lambs that was effective when the lambs were challenged. ‘Arc 5’ antibodies were induced by prolonged infection with cysts, and were not seen in the sera of ewes immunized with eggs, although the eggs developed into cysts at the injection sites. ‘Arc 5’ antibodies did not protect lambs against infection, and were not correlated with protection in ewes. Subcutaneous injection of oncospheres into four ewes from each group at the time of lamb challenge showed that the immunized ewes were immune to this method of challenge, but the infected and control ewes were not. Ewes and lambs of the immunized group, and to a lesser extent the 2-year-infected group, had in vitro oncosphere-killing capacity in their serum collected 1 week after parturition, while those from the control group did not. Killing capacity in the sera of two hyperimmunized lambs was predominantly in the IgG2 subclass. It would appear that the IgG1 subclass, which is the major immunoglobulin in ewe colostrum, either does not carry protective antibodies, or is not able to participate in killing oncospheres in vivo in young lambs.

Letters to the editors

Abstract Extract Madam:- Since a number of animal diseases such as brucellosis and tuberculosis in cattle, and hydatids in sheep are now reaching a low prevalence (P: percentage of diseased animals in a population), it is perhaps appropriate to remind readers that prevalence has a marked influence on the accuracy with which a diagnostic test can identify diseased animals. Whereas an ideal test will give positive results with all diseased animals and negative results with all disease-free animals, the ideal is rarely attainable and most tests return some false positive and false negative results. Many published diagnostic tests(2) Hamel, K.L. and Ris, D.R. 1982. The use of a cathodic antigen in the immunoelectro-phoretic serodiagnosis of Echinococcus granulosus in sheep. Vet. Immunol. Immunopathol., 3: 419–425. [Google Scholar] (4) Ris, D.R. 1974. The complement fixation test for the diagnosis of Brucella ovis infection in sheep. N.Z. vet. J., 22: 143–146. [Taylor & Francis Online] , [Google Scholar] (5) Worthington, R.W., Weddell, W. and Penrose, M.E. 1984. A comparison of three serological tests for the diagnosis of B. ovis infection in rams. N.Z. vet. J., 32: 58–60. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar] have a sensitivity (Se: percentage of diseased animals with a positive result) and a specificity (Sp: percentage of disease-free animals with a negative result) of between 90 and 100%, and perform well when the prevalence of a particular disease is high. But, when it is low, as is the case when a disease is nearly eradicated, or in a group of animals selected for export, the same tests have a much lower accuracy in the detection of diseased animals. (3) Moffat, J. 1985. Grasping the nettle on Tb in deer. N.Z. J. Agrie., 150(7): 4–7. [Google Scholar] It is not the tests that have changed, but the conditions under which they are used.

On Acquired Immunity to Echinococcus granulosus in Sheep

SUMMARY Absolute resistance to superinfection by Echinococcus granulosus in sheep was not stimulated within 9 months. Partial resistance, however, appeared to occur, particularly after a high initial dose. An overall decrease occurred in the serum albumin/globulin ratios in sheep with short-term infections of E. granulosus superimposed on chronic infections. With hydatid fluid as antigen, indirect haemagglutination titres of 1:400 or more indicated an infection of E. granulosus in sheep. Only a low level (1:200 or lower) of cross-reactivity was demonstrated by Taenia hydatigena, T. ovis, Multiceps multiceps and Linguatula serrata. Sheep that initially received large numbers of eggs (2000 to 100,000) showed titres of the order of 1:3200 at 9 months. After the challenge dose of eggs, the titres in these animals were not markedly changed. The superimposed infections in the animals fed 1000 eggs or fewer at the initial dose raised the titre 2- to 4-fold.

An analysis of the incidence of hydatid cysts (Echinococcus granulosus) in domestic food animals in New Zealand, 1958–1959

Abstract Extract Although New Zealand is alleged to have one of the highest incidences of hydatid disease per head of the human population in the British Commonwealth (Foster, 1958), little precise information is available on the incidence of the parasite in livestock. In 1958, a survey was carried out to determine the incidence of cysts of Echinococcus granulosus in sheep in the South Island. In 1959, the survey was repeated in the North Island. A third and smaller, but more detailed, survey was also undertaken in 1959. These surveys were undertaken, however, after preliminary steps had been taken to control the hydatid parasite and thus cannot be regarded as true base-line figures. This paper therefore records the incidence of E. granulosus as observed in 1958–59 and thus forms a base-line from this time.