Trichuris Species Research Articles

Gastro-Intestinal Helminthes of Slaughtered Cattle at Wukari Abattoir Taraba State, North-Eastern Nigeria

Studies were conducted to determine the prevalence of helminthes parasites affecting cattle slaughtered at the Wukari Local Government abattoir, in Taraba State North-Eastern Nigeria. The Standard saturated salt (NaCl) floatation technique was used, and examined microscopically to determine the parasites and the number of eggs per gram. Of the 350 samples examined 122 (34.90%) were infected with one or more intestinal helminthes. In order of prevalence, Paramphistomum species recorded 83 (23.70%); Oesophagastomum radiatum 50 (14.30%); Fasciola gigantica 31 (8.90%); Trichuris species 28 (8.00%) and Monezia expansa 23 (6.60%). A Chi-Squared analysis revealed that the prevalence of Gastro-intestinal helminthes between male and female animals varied significantly, so it is between the young and the adult cattle (P<0.05). Of the 163 male cattle examined, a higher prevalence of 62 (38.04%) was observed when compared to the 60 (32.10%) of their female counterpart out of the 187 examined. The young cattle between the ages of 0-23 months were more susceptible to the intestinal parasites infection having a prevalence of 43 (45.30%) than the adult examined who had 79 (30.10%). The result of this study shows a high prevalence of Gastro-intestinal parasites among the slaughtered cattle in Wukari. Farmer's awareness and national campaigns are highly recommended.

The first determination of Trichuris sp. from roe deer by amplification and sequenation of the ITS1-5.8S-ITS2 segment of ribosomal DNA

Trichuris nematodes were isolated from roe deer (Capreolus capreolus). At first, nematodes were determined using morphological and biometrical methods. Subsequently genomic DNA was isolated and the ITS1-5.8S-ITS2 segment from ribosomal DNA (RNA) was amplified and sequenced using PCR techniques. With u sing morphological and biometrical methods, female nematodes were identified as Trichuris globulosa, and the only male was identified as Trichuris ovis. The females were classified into four morphotypes. However, analysis of the internal transcribed spacers (ITS1-5.8S-ITS2) of specimens did not confirm this classification. Moreover, the female individuals morphologically determined as T. globulosa were molecularly identified as Trichuris discolor. In the case of the only male molecular analysis match the result of the molecular identification. Furthermore, a comparative phylogenetic study was carried out with the ITS1 and ITS2 sequences of the Trichuris species from various hosts. A comparison of biometric information from T. discolor individuals from this study was also conducted.

Sem Studies on Trichurus Muris from Psammomys Obessus from Sinai Peninsula , Egypt

The whipworm Trichuris muris was recovered from the caecum of the wild rodent Psammomys obessus trapped from Sinai Peninsula, Egypt. The cuticular surface ultrastructure is described using SEM. T. muris is closely related to other Trichuris species but can be distinguished from them mainly by differences in the posterior end of males. Details of the surface such as the bacillary gland, cuticular inflations and several morphological details obtained by scanning electron microscopy confirmed the characteristics that differentiate the species. P. obessus (Cretzschmar, 1828) is considered a new host record and Sinai is considered a new locality for the genus. This may through light on the spread of T. muris between Asia and Africa.

Clear genetic distinctiveness between human- and pig-derived Trichuris based on analyses of mitochondrial datasets.

The whipworm, Trichuris trichiura, causes trichuriasis in ∼600 million people worldwide, mainly in developing countries. Whipworms also infect other animal hosts, including pigs (T. suis), dogs (T. vulpis) and non-human primates, and cause disease in these hosts, which is similar to trichuriasis of humans. Although Trichuris species are considered to be host specific, there has been considerable controversy, over the years, as to whether T. trichiura and T. suis are the same or distinct species. Here, we characterised the entire mitochondrial genomes of human-derived Trichuris and pig-derived Trichuris, compared them and then tested the hypothesis that the parasites from these two host species are genetically distinct in a phylogenetic analysis of the sequence data. Taken together, the findings support the proposal that T. trichiura and T. suis are separate species, consistent with previous data for nuclear ribosomal DNA. Using molecular analytical tools, employing genetic markers defined herein, future work should conduct large-scale studies to establish whether T. trichiura is found in pigs and T. suis in humans in endemic regions.

16S partial gene mitochondrial DNA and internal transcribed spacers ribosomal DNA as differential markers of Trichuris discolor populations

Comparative morphological, biometrical and molecular studies of Trichuris discolor isolated from Bos taurus from Spain and Iran was carried out. Furthermore, Trichuris ovis isolated from B. taurus and Capra hircus from Spain has been, molecularly, analyzed. Morphological studies revealed clear differences between T. ovis and T. discolor isolated from B. taurus but differences were not observed between populations of T. discolor isolated from different geographical regions. Nevertheless, the molecular studies based on the amplification and sequencing of the internal transcribed spacers 1 and 2 ribosomal DNA and 16S partial gene mitochondrial DNA showed clear differences between both populations of T. discolor from Spain and Iran suggesting two cryptic species. Phylogenetic studies corroborated these data. Thus, phylogenetic trees based on ITS1, ITS2 and 16S partial gene sequences showed that individuals of T. discolor from B. taurus from Iran clustered together and separated, with high bootstrap values, of T. discolor isolated from B. taurus from Spain, while populations of T. ovis from B. taurus and C. hircus from Spain clustered together but separated with high bootstrap values of both populations of T. discolor. Furthermore, a comparative phylogenetic study has been carried out with the ITS1and ITS2 sequences of Trichuris species from different hosts. Three clades were observed: the first clustered all the species of Trichuris parasitizing herbivores (T. discolor, T. ovis, Trichuris leporis and Trichuris skrjabini), the second clustered all the species of Trichuris parasitizing omnivores (Trichuris trichiura and Trichuris suis) and finally, the third clustered species of Trichuris parasitizing carnivores (Trichuris muris, Trichuris arvicolae and Trichuris vulpis).

&lt;em&gt;Trichuris muris&lt;/em&gt; Infection: A Model of Type 2 Immunity and Inflammation in the Gut

Trichuris muris is a natural pathogen of mice and is biologically and antigenically similar to species of Trichuris that infect humans and livestock. Infective eggs are given by oral gavage, hatch in the distal small intestine, invade the intestinal epithelial cells (IECs) that line the crypts of the cecum and proximal colon and upon maturation the worms release eggs into the environment. This model is a powerful tool to examine factors that control CD4(+) T helper (Th) cell activation as well as changes in the intestinal epithelium. The immune response that occurs in resistant inbred strains, such as C57BL/6 and BALB/c, is characterized by Th2 polarized cytokines (IL-4, IL-5 and IL-13) and expulsion of worms while Th1-associated cytokines (IL-12, IL-18, IFN-γ) promote chronic infections in genetically susceptible AKR/J mice. Th2 cytokines promote physiological changes in the intestinal microenvironment including rapid turnover of IECs, goblet cell differentiation, recruitment and changes in epithelial permeability and smooth muscle contraction, all of which have been implicated in worm expulsion. Here we detail a protocol for propagating Trichuris muris eggs which can be used in subsequent experiments. We also provide a sample experimental harvest with suggestions for post-infection analysis. Overall, this protocol will provide researchers with the basic tools to perform a Trichuris muris mouse infection model which can be used to address questions pertaining to Th proclivity in the gastrointestinal tract as well as immune effector functions of IECs.

New Species of Trichuris (Nematoda: Trichuridae) from Akodon montensis Thomas, 1913, of the Paranaense Forest in Argentina

Species of Trichuris (Nematoda:Trichuridae) parasitize a broad range of mammalian hosts. To date, 21 Trichuris species infecting nine families of rodents have been found in North and South America. Trichuris navonae n. sp. is described on the basis of specimens recovered from a species of forest-dwelling mice, Akodon montensis (Cricetidae: Sigmodontinae), from nine localities of Misiones Province, Argentina. A comparison with all the species of Trichuris from North and South American rodents is given. The separation of the new species of Trichuris is based on morphologic and morphometrica features, such as the absence of a spicular tube, the presence of a cylindrical spicular sheath with sharp spines, a non-protrusive vulva, a long anterior-posterior portion of the body, a lengthy spicule, and a proximal and distal cloacal tube. This is the third record of this genus in rodents of the Sigmodontinae from Argentina and the fifth record from South American rodents. Despite the large number of potential host species, only about 1.9% of sigmodontine rodent species have been reported as hosts of Trichuris spp. It is suggested that this number represents but a small fraction of Trichuris spp. that occur in sigmodontine rodents, and that additional survey of this group should yield additional species.

Case report of helminths and lung mite infection in the red-tailed monkey, Cercopithecus ascanius schmidti, in Mahale Mountains National Park, Tanzania

We documented the presence of gastrointestinal nematodes and lung mites in two red-tailed monkeys, Cercopithecus ascanius schmidti, in Mahale Mountains National Park, Tanzania. We detected lung mites, Pneumonyssus duttoni, in the trachea and bronchioles, and five species of nematodes, Oesophagostomum pachycephalum, Ternidens deminutus, Streptopharagus pigmentatus, Primasubulura distans, and Trichuris sp. in their gastrointestinal tracts. This is the first report of a parasitological survey for the red-tailed monkey in Mahale Mountains National Park, and O. pachycephalum, T. deminutus, and P. distans were found for the first time in the red-tailed monkey.

Amplification and sequencing of Trichuris trichiura ancient DNA extracted from archaeological sediments

Despite high prevalence of Trichuris trichiura infection, PCR-based analysis on T. trichiura from archaeological samples has not been established so far. In the present study, we sought to perform PCR-based amplification of T. trichiura aDNA using the sediments from medieval tomb of Korea. The presence of Trichuris eggs were first detected by microscopic observation; then confirmed by PCR-based aDNA analysis. Obtained sequence showed 100% homology to that of the small subunit ribosomal RNA (SSUrRNA) gene of T. trichiura but distinct from that of other Trichuris species. PCR-based aDNA analysis in this study can serve as effective method to confirm the presence of T. trichiura eggs in the soils or coprolites collected from archaeological sites.

Trichuris suis and Trichuris trichiura are different nematode species

In this paper, a morphological and biometrical study by optical microscopy and scanning electronic microscopy (SEM) of Trichuris suis isolated from different hosts ( Sus scrofa domestica and Sus scrofa scrofa) and Trichuris trichiura isolated from chimpanzee, has been carried out. Our results demonstrate the existence of typical pericloacal papillae in both species. Biometrical parameters of T. suis and T. trichiura overlapped but males and females of T. trichiura tended to be shorter and thinner than those of T. suis. Our results suggest that T. suis and T. trichiura cannot be differentiated using standard procedures as morphological and biometrical determinations. Thus, the ITS1-5.8S-ITS2 region of the ribosomal DNA was sequenced to allow a differentiation between T. suis and T. trichiura on genetic level. The ITS1 and ITS2 sequences derived from T. trichiura eggs isolated from feces of primates ( Colobus guereza kikuyensis and Nomascus gabriellae) showed clear differences to the respective sequences of T. suis derived from eggs of different porcine hosts. The 5.8S gene was similar between the two species. Sequences obtained from different populations of the same species showed no significant differences indicating that the ITS1-5.8S-ITS2 sequences reported in this study are representative for T. trichiura and T. suis, respectively. Phylogenetic relationships have been determined attending to the ITS1 and ITS2 sequences from different species of the genus Trichuris. In conclusion, T. trichiura and T. suis are considered to be closely related but genetically different species. Both species can be easily and reliably distinguished by a PCR-RFLP analysis of the ITS1 and ITS2 sequences with different restriction enzymes.

Characterization and PCR multiplexing of polymorphic microsatellite loci in the whipworm Trichuris arvicolae, parasite of arvicoline rodents and their cross-species utilization in T. muris, parasite of murines

Trichuris arvicolae and T. muris are gastro-intestinal nematodes of respectively arvicoline and murine rodents. We aim to investigate the ecology of these Trichuris species using population genetics. We sampled nematodes from rodents trapped in the East of France. After confirming the species identification of the nematodes using ITS1–5.8S–ITS2 ribosomal DNA sequences, we isolated and characterized twelve dinucleotide microsatellite loci in T. arvicolae. A multiplex panel was developed. Application to a set of 30 individuals allowed clear and easy characterization of allele sizes. The number of alleles ranged from 2 to 6 per locus with observed heterozygosities ranging from 0 to 0.93. A test on eleven T. muris revealed that eight loci among twelve amplified, and five were polymorphic. These sets of microsatellite loci provide high throughput capacity for population genetic studies.

Plasmodium falciparum and helminth coinfection in a semi urban population of pregnant women in Uganda.

Helminth infections and malaria are widespread in the tropics. Recent studies suggest helminth infections may increase susceptibility to Plasmodium falciparum infection. If confirmed, this increased susceptibility could be particularly important during pregnancy-induced immunosuppression. To evaluate the geographical distribution of P. falciparum-helminth coinfection and the associations between P. falciparum infection and infection with various parasite species in pregnant women in Entebbe, Uganda. A cross-sectional study was conducted at baseline during a trial of antihelminthic drugs during pregnancy. Helminth and P. falciparum infections were quantified in 2,507 asymptomatic women. Subjects' socioeconomic and demographic characteristics and geographical details were recorded. Hookworm and Mansonella perstans infections were associated with P. falciparum infection, but the effect of hookworm infection was seen only in the absence of M. perstans infection. The odds ratio [OR] for P. falciparum infection, adjusted for age, tribe, socioeconomic status, HIV infection status, and location was as follows: for individuals infected with hookworm but not M. perstans, 1.53 (95% confidence interval [CI], 1.09-2.14); for individuals infected with M. perstans but not hookworm, 2.33 (95% CI, 1.47-3.69); for individuals infected with both hookworm and M. perstans, 1.85 (CI, 1.24-2.76). No association was observed between infection with Schistosoma mansoni, Trichuris, or Strongyloides species and P. falciparum infection. Hookworm-P. falciparum coinfection and M. perstans-P. falciparum coinfection among pregnant women in Entebbe is more common than would be expected by chance. Further studies are needed to elucidate the mechanism of this association. A helminth-induced increase in susceptibility to P. falciparum could have important consequences for pregnancy outcome and responses to P. falciparum infection in infancy.

Prevalence and seasonal changes in the population of gastrointestinal nematodes of small ruminants in the semi-arid zone of north-eastern Nigeria

A survey was carried out to determine the prevalence and seasonal abundance of the egg and adult stages of nematode parasites of sheep and goats in the semi-arid zone of north-eastern Nigeria between January and December 2002. Faecal samples collected from 102 sheep and 147 goats and examined by the modified McMaster technique using saturated solution of sodium chloride as the floating medium revealed that 44 (43.1%) and 82 (55.8%) of the samples, respectively, contained at least one nematode egg type. Three nematode egg types were recovered with strongyle egg type (22.5% in sheep and 35.4% in goats) being the most prevalent followed, respectively, by Trichuris (5.9% in sheep and 4.1% in goats) and Strongyloides (4.9% in sheep and 4.1% in goats) egg types. Mean faecal egg counts were generally moderate in both sheep (1052 ± 922 strongyle, 1000 ± 590 Strongyloides and 380 ± 110 Trichuris eggs, respectively, per g of faeces) and goats (2092 ± 3475 strongyle, 958 ± 854 Strongyloides and 683 ± 512 Trichuris eggs, respectively, per g of faeces) and showed the same trend irrespective of the age or sex of the animals. The prevalence and counts of strongyle nematode eggs showed a definite seasonal sequence that corresponded with the rainfall pattern in the study area during the period. In both sheep and goats, counts of strongyle egg type increased with the rains and reached peak levels at about the peak of the rainy season in September. The other egg types encountered during the study did not show much variation with the season of the year. Out of the 45 sheep and 75 goats examined at necropsy, 27 (60%) and 39 (52%), respectively, contained adult nematode species. Seven genera of adult nematodes including Strongyloides, Trichostrongylus, Haemonchus, Trichuris, Cooperia, Oesophagostomum and Bunostomum species were encountered during the study. Bunostomum species were recorded only in sheep. Adult worm burdens were generally low and showed seasonal variation that corresponded with the rainfall pattern in the study area during the period. Haemonchus and Trichostrongylus species attained peak counts together in both goats (June) and sheep (August). Strongyloides species were encountered throughout the year in both sheep and goats irrespective of the season. Other genera of nematodes encountered occurred in very low numbers and did not allow any meaningful comparison of seasonal sequence. The results suggest that Haemonchus, Trichostrongylus and Strongyloides species may be the major contributors to small ruminant helminthiasis in the study area.

A NEW SPECIES OF TRICHURIS (NEMATODA: TRICHURIDAE) FROM PHYLLOTINI RODENTS IN ARGENTINA

A new species of Trichuris is described. Trichuris pardinasi n. sp. was recovered from Phyllotis xanthopygus Waterhouse (Rodentia: Muridae: Phyllotini) in Sierra de la Ventana, Buenos Aires Province, and Pampa de Achala, Córdoba Province (Argentina). This is the first record of Trichuris parasitizing Phyllotini rodents. The new species can be differentiated from the other 10 species parasitizing rodents from South America by the absence of the spicular tube, spicular sheath with spines uniformly distributed, the length of spicule, the J-shaped proximal cloacal tube, and the nonprotrusive vulva. Also, a description of the bacillary band is provided. The present and the future findings of shared parasite fauna from both populations of P. xanthopygus in these disjunct areas will support the hypothesis of a continuous distribution of this host species at a past time.

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Determination of Trichuris muris from murid hosts and T. arvicolae (Nematoda) from arvicolid rodents by amplification and sequentiation of the ITS1-5.8S-ITS2 segment of the ribosomal DNA.

Trichuris muris has been isolated from murid hosts ( Apodemus sylvaticus and Mus musculus) and Trichuris arvicolae from arvicolid rodents in Barcelona, Spain. Genomic DNA was isolated and the ITS1-5.8S-ITS2 segment from the ribosomal DNA (rDNA) was amplified and sequenced using polymerase chain reaction techniques. The ITS2 of both populations isolated from Apodemus and Mus was 382 nucleotides in length and had a GC content of about 60.73%, while the ITS2 of T. arvicolae was 442 nucleotides in length and had a GC content of about 59.8%. Furthermore, the ITS1 of Trichuris from murids was 448 nucleotides in length and had a GC content of about 56.47%, while T. arvicolae was 446 nucleotides in length and had 57.62% of GC content. A total of 161 and 173 nucleotides were observed along the 5.8S gene of T. murisand T. arvicolae, respectively; This difference in nucleotides was due to the insertion of a DNA segment (transposon) in the 5.8S sequence of the latter species. Slight intraindividual and intraspecific variations were detected in the rDNA of both species. The presence of microsatellites was observed in all of the individuals assayed. Sequence analysis of the internal transcribed spacers and the 5.8S gene demonstrated no sequence differences between T. muris isolated from both of its murid hosts. Nevertheless, clear differences were detected between the ITS2, ITS1 and 5.8S gene of T. muris and T. arvicolae. This corroborates the existence of two separate Trichuris species in murid and arvicolid hosts. Furthermore, a phylogenetic analysis was carried out and endonucleases restriction maps were elaborated for both species.

Present status of ovine helminthosis in some of western provinces of Iran.

A survey was carried out to determine the prevalence and seasonal abundance of the egg and adult stages of nematode parasites of sheep and goats in the semi-arid zone of north-eastern Nigeria between January and December 2002. Faecal samples collected from 102 sheep and 147 goats and examined by the modified McMaster technique using saturated solution of sodium chloride as the floating medium revealed that 44 (43.1%) and 82 (55.8%) of the samples, respectively, contained at least one nematode egg type. Three nematode egg types were recovered with strongyle egg type (22.5% in sheep and 35.4% in goats) being the most prevalent followed, respectively, by Trichuris (5.9% in sheep and 4.1% in goats) and Strongyloides (4.9% in sheep and 4.1% in goats) egg types. Mean faecal egg counts were generally moderate in both sheep (1052 ± 922 strongyle, 1000 ± 590 Strongyloides and 380 ± 110 Trichuris eggs, respectively, per g of faeces) and goats (2092 ± 3475 strongyle, 958 ± 854 Strongyloides and 683 ± 512 Trichuris eggs, respectively, per g of faeces) and showed the same trend irrespective of the age or sex of the animals. The prevalence and counts of strongyle nematode eggs showed a definite seasonal sequence that corresponded with the rainfall pattern in the study area during the period. In both sheep and goats, counts of strongyle egg type increased with the rains and reached peak levels at about the peak of the rainy season in September. The other egg types encountered during the study did not show much variation with the season of the year. Out of the 45 sheep and 75 goats examined at necropsy, 27 (60%) and 39 (52%), respectively, contained adult nematode species. Seven genera of adult nematodes including Strongyloides, Trichostrongylus, Haemonchus, Trichuris, Cooperia, Oesophagostomum and Bunostomum species were encountered during the study. Bunostomum species were recorded only in sheep. Adult worm burdens were generally low and showed seasonal variation that corresponded with the rainfall pattern in the study area during the period. Haemonchus and Trichostrongylus species attained peak counts together in both goats (June) and sheep (August). Strongyloides species were encountered throughout the year in both sheep and goats irrespective of the season. Other genera of nematodes encountered occurred in very low numbers and did not allow any meaningful comparison of seasonal sequence. The results suggest that Haemonchus, Trichostrongylus and Strongyloides species may be the major contributors to small ruminant helminthiasis in the study area.

Antibody isotype responses to Trichuris infection in humanized SCID mice.

We have developed a humanized SCID mouse model of trichuriasis involving the injection of peripheral blood lymphocytes (PBLs) from normal healthy donors into C. B. 17 severe combined immunodeficiency (SCID) mice followed by vaccination and infection of these mice with the murine species of Trichuris, Trichuris muris. Optimal results with respect to parasite specific antibody production and peripheral engraftment were achieved by injecting intraperitoneally 2 x 10(7) PBLs which had been incubated overnight on anti-human CD3 coated plates. Mice were immunized three weeks post reconstitution with parasite antigen in Freund's Incomplete Adjuvant and infected two weeks later. At autopsy human T cells could be detected in the spleens of engrafted animals and anti-T. muris antibody detected. The dominant IgG isotype responses were shown to be IgG1 and IgG2, providing a similar IgG isotype profile to that seen in humans infected with T. trichiura in the field. In several cases engrafted animals showed the remarkable ability to expel their parasite load. The model will thus be useful for analysing human immune responses to trichuriasis under highly controlled laboratory conditions impossible to achieve in the field.

Gastro-Intestinal Nematodes and Seasonal Activities in Sheep in the Kars District

In this study, the gastro-intestinal organs of the 100 sheep were examined for the gastro-intestinal nematodes and their seasonal activities between September 1992 - August 1994, in Kars district, in Turkey. All the examined animals were infected with the gastrointestinal nematodes. In sheep 29 nematode species were determined. The 440253 nematodes were collected from infected sheep. The total number of parasites for each animals were ranged between 2-31570. The average number of parasites in sheep were determined as 4402.5. The number of nematode species for each animals were ranged betweed 1-13 (mean 6.1). Dominant species in infected sheep were determined as follows: Trichostrongylus colubriformis (66%), T. skrjabini (63%), Marshallagia marshalli (63%), Ostertagia circumcincta (56%) and Trichuris skrjabini (55%). Ostertagia lyrata, Capillaria bovis and Trichuris discolor were found for the first time in sheep in Turkey. Ostartagia, Trichostrongylus, Nematodirus, Trichuris species and B. trigonocephalum and M. marshalli were detected in sheep in all seasons of two years, but the highest infection lewel was noted in Ostertagia spp. in summer, Trichostrongylus spp. and M. marshalli in autumn and winter, Trichuris and Nematodirus spp. in summer and autumn. The infection level of the B. trigonocephalum was not uniform along the seasons.

Characterization of Trichuris skrjabini by isoenzyme gel electrophoresis: comparative study with Trichuris ovis

Morphological and biometric studies were performed in Trichuris skrjabini (Baskakov, 1924) collected from the caecum of Capra hircus. The LDH (EC 1.1.1.27.), G6PD (EC 1.1.1.49.), GPI (EC 5.3.1.9.), MDH (EC 1.1.1.37) and malic enzyme (ME) (EC 1.1.1.40) isoenzymatic patterns of T. skrjabini were determined by starch gel electrophoresis. The G6PD and GPI isoenzymatic patterns of T. skrjabini displayed two anodic bands for both enzymes: one fast migration band and one band near the origin. This isoenzymatic pattern was interpreted as two gene loci encoding both enzymes. The LDH isoenzymatic pattern of T. skrjabini was characterized by the presence of a cathodically migrating band, while the MDH isoenzymatic pattern showed a very slow cathodic band. These two phenotypes were interpreted as the expression of a homozygous state of a gene locus for LDH and MDH in T. skrjabini. The ME isoenzymatic pattern was characterized by the presence of a single anodic band. Further, comparative isoenzymatic studies were carried out between T. skrjabini and T. ovis. The different G6PD, GPI, LDH, MDH and ME isoenzymatic patterns observed for both species allowed us to distinguish them and therefore to use isoenzymatic patterns as a diagnostic tool to differentiate species of Trichuris.