Divergence across mitochondrial genomes of sympatric members of the Schistosoma indicum group and clues into the evolution of Schistosoma spindale

Schistosoma spindale and Schistosoma indicum are ruminant-infecting trematodes of the Schistosoma indicum group that are widespread across Southeast Asia. Though neglected, these parasites can cause major pathology and mortality to livestock leading to significant welfare and socio-economic issues, predominantly amongst poor subsistence farmers and their families. Here we used mitogenomic analysis to determine the relationships between these two sympatric species of schistosome and to characterise S. spindale diversity in order to identify possible cryptic speciation. The mitochondrial genomes of S. spindale and S. indicum were assembled and genetic analyses revealed high levels of diversity within the S. indicum group. Evidence of functional changes in mitochondrial genes indicated adaptation to environmental change associated with speciation events in S. spindale around 2.5 million years ago. We discuss our results in terms of their theoretical and applied implications.

Prevalence of Haemonchosis of Goats at Rajshahi District in Bangladesh

A study was conducted in the Laboratory of Animal Husbandry and Veterinary Science, University of Rajshahi, Rajshahi, Bangladesh, during March, 2011 to February, 2012. The aim of this study was to determine the effects of temperature, humidity and rainfall in different months on the prevalence of haemonchosis of goats in Rajshahi, Bangladesh. A total of 720 samples were examined, of these (416) 57.8% goats were found positive for Haemonchus spp. infection. The highest prevalence was observed in the month of July (82.1 %) followed by August (79.7 %) and lowest in the January (28.3 %) followed by February (38.7 %). It was also observed that temperature (29.8°?), relative humidity (86%) and rainfall (146.0 mm) in the month of July was favourable for the egg laying, hatching and survival of infective larvae on the pasture. On the other hand, all the factors like temperature, humidity and rainfall was recorded lowest as 17.5°?, 79%, 5.5 mm respectively which was unfavourable for the reproduction and survival of infective larvae in the month of the January. The current study revealed that haemonchosis is an important and common parasitic disease and requires special attention for its control.  The prevalence among different months when compared statistically (Chi-square test and DMRT) revealed significant (P=0.001) differences. So, it is concluded that, month of the year, temperature, humidity and rainfall has significance effect on the prevalence of haemonchosis in goats. Considering those factors control should be carried out in and around Bangladesh to improve our goat production.DOI: http://dx.doi.org/10.3329/bjvm.v13i1.23713Bangl. J. Vet. Med. (2015). 13 (1): 29-36

A CROSS SECTIONAL STUDY ON FASCIOLA GIGANTICA AND GIGANTOCOTYLE EXPLANATUM BURDENS IN NATURALLY INFECTED BUFFALOES IN BANGLADESH

A cross sectional study on Fasciola gigantica and Gigantocotyle explanatum burdens in buffaloes in relation to their age, sex and health condition was carried out in the Laboratory of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh during the period from June to November 1997. A total of 460 faecal samples were examined to determine the egg per gram of faeces (epg) of F. gigantica. Higher epg was counted in female buffaloes (159.67 ± 6.80) than in males (153.24 ± 8.29). The epg counts were also found significantly (p < 0.01) higher in poor conditioned buffaloes (164.41 ± 6.67) than in buffaloes with normal health (128.57 ± 7.08). In relation to age, the young adult buffaloes were found to bear more parasitic burdens. The highest mean epg was recorded in the buffaloes of 2-3 years old (184.21 ± 19.14), followed by 3-5 years old (169.23 ± 30.77). The older buffaloes had relatively lower parasitic burden and the lowest mean epg was recorded in the growing buffaloes of up to 1 year old (125 ± 25.0). Examination of 106 livers from slaughtered buffaloes, revealed that the load of Fasciola gigantica and Gigantocotyle explanatum in the livers ranged from 13-424 (69.20 ± 6.46) and 41-427 (161.45 ± 10.79) respectively. In males the burden of F. gigantica (13-210) was lower than that of the females (15-424). The mean number of F. gigantica in the buffaloes of 5- 10 years old (100 ± 15.32) was significantly higher (p < 0.01) than those of the buffaloes of above 10 years old (52.92 ± 4.29). In case of single infection with F. gigantica, the mean number of parasites per liver was significantly (p < 0.05) higher (88.70 ± 11.48) than that of mixed infection cases (49.74 ± 4.20). Significantly (p < 0.01) higher number of G. explanatum was recovered from the buffaloes of 5-10 years old (207.53 ± 26.72) than from the buffaloes of above 10 years old (141.58 ± 9.23) and from single infected cases than from buffaloes with mixed infection. There were almost no differences in the number of both flukes in relation to sex of buffaloes. The length and breadth of immature and mature parasites were 5-15 min x 2-3 min and 16-72 mm x 4-14 mm respectively. No significant variation was found in the average size of F. gigantica in relation to the age and sex of buffaloes. But in case of single infection, the body size of mature F. gigantica (38.63 mm ± 0.38 mm x 9.96 mm ± 0.12 mm) was significantly (p < 0.05) higher than that of the mixed infection (33.68 mm ± 0.52 mm x 8.76 mm ± 0.07 mm) cases. This study fairly suggests that the young adult buffaloes harbour more F. gigantica parasites than their younger and older counterparts. The concomitant infection of buffaloes with F. gigantica and G. explanatum may hamper the parasites each other in establishing their infection and attaining growth in some way as measured by their burdens and morphological dimensions.

A DNA sequence-based study of theSchistosoma indicum(Trematoda: Digenea) group: population phylogeny, taxonomy and historical biogeography

Partial (DNA) sequences were collected for 2 mitochondrial loci (SrrnaandLrrna, therrnS andrrnL rRNA genes respectively) forSchistosoma indicumgroup species from 4 Southeast Asian countries. The samples included 7 populations, 4 of which were previously unstudied. In 11 cases the combination of locus and population was new. The aim of the study was to provide a phylogeny based on new independent data and multiple populations (earlier studies had mostly used a common set of field samples or laboratory lines) and to examine interrelationships and phylogeography within this species group. Paraphyly of theS. indicumgroup was confirmed, as was the basal position ofSchistosoma incognitumin theSchistosomaphylogeny. Southeast AsianSchistosoma spindaleandS. incognitumpopulations were shown to fall into their respective con-specific cohesive groupings. Estimated divergence times for these taxa were shown to be related to Pleistocene changes in sea level and the radiation of definitive host groups. A revised phylogeographical model is proposed in the light of these findings.

Affinities between Asian non-human Schistosoma species, the S. indicum group, and the African human schistosomes

Schistosoma species have traditionally been arranged in groups based on egg morphology, geographical origins, and the genus or family of snail intermediate host. One of these groups is the 'S. indicum group' comprising species from Asia that use pulmonate snails as intermediate hosts. DNA sequences were obtained from the four members of this group (S. indicum, S. spindale, S. nasale and S. incognitum) to provide information concerning their phylogenetic relationships with other Asian and African species and species groups. The sequences came from the second internal transcribed spacer (ITS2) of the ribosomal gene repeat, part of the 28S ribosomal RNA gene (28S), and part of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene. Tree analyses using both distance and parsimony methods showed the S. indicum group not to be monophyletic. Schistosoma indicum, S. spindale and S. nasale were clustered among African schistosomes, while S. incognitum was placed as sister to the African species (using ITS2 and 28S nucleotide sequences and CO1 amino acid sequences), or as sister to all other species of Schistosoma (CO1 nucleotide sequences). Based on the present molecular data, a scenario for the evolution of the S. indicum group is discussed.

EPIDEMIOLOGY OF ECTOPARASITIC INFESTATIONS IN CATTLE AT BHAWAL FOREST AREA, GAZIPUR

To determine the prevalence of ectoparasitic infestation of cattle in and around the Bhawal forest area in Gazipur district in Bangladesh, an epidemiological investigation was carried out during the period from November 2008 to October 2009. Of 206 cattle examined, 132 (64.07%) were found to be infested with several species of ticks and lice. The prevalence rate was highest in case of Boophilus microplus (45.63%) followed by Rhipicephalus sanguineus (36.89%), Linognathus vituli ((23.30%), Haematopinus euysternus (17.96%), Hemaphysalis bispinosa (16.50%), and Damalinia bovis (8.25%). Results revealed that, older cattle aged > 8 years are more (71.11%) susceptible than that of adults aged > 2-8 years (67.74%), and young aged ≤2 years (47.05%). In females, prevalence of ectoparasitic infestation was observed significantly (p< 0.005) higher than that of male. Prevalence of ectoparasitic infestation was significantly (p<0.005) higher in animal reared under free range system than that of semi-intensive system and cattle with malnourished and poor health status were found to be significantly more vulnerable to such parasitic infestation than normal healthy cattle. Seasonal prevalence showed that, significantly (p<0.001) higher prevalence occurred in summer season (78.46%), followed by winter (62.85%) and rainy season (52.11%). Mean parasitic burden were 1.49±0.80 per square inches of heavily infected area. DOI = 10.3329/bjvm.v8i1.7399 Bangl. J. Vet. Med. (2010). 8(1): 27-33

Seasonal Influence on The Occurrence of Haemonchus contortus Infection in Slaughtered Black Bengal Goats in Bangladesh

Seasonal influence on the occurrence of Haemonchus contortus parasite was studied on 672 slaughtered Black Bengal goats during one year period from July 2002 to June 2003. An overall 65.63% goats had H. contortus infection and significantly (p < 0.01) higher infection rate was recorded in female (70.43%) than male (58.61%) goats. A positive correlation between the occurrence of H. contortus infection and climatic factors was recorded. Significantly (p < 0.01) highest infection rate of H. contortus was recorded during rainy (72.57 %) season in comparison to summer (66.46%) and winter (51.54%) seasons. The infection was recorded at the peak in July (84.42%) and lowest in January (46.15%). The load of H. contortus per abomasum varied significantly (p < 0.05) in different months of the year and an average maximum number of parasites per abomasum was recorded in July (41.25) and the minimum in March (5.52). In case of sex ratio of the parasites always the female (60.73%) were found to be dominated over the males (39.27%) parasites.     Key words: Seasonal influence; Haemonchus contortus; Black Bengal goat; Bangladesh DOI = 10.3329/bjvm.v1i1.1917 Bangl. J. Vet. Med. (2003). 1(1) : 45 - 48

In vitro efficacy of some indigenous plants on the inhibition of development of eggs of Ascaridia galli (Digenia: Nematoda)

In vitro efficacy of five indigenous plants namely Bishkatali (Polygonum hydropiper), Neem (Azadirachta indica), Papaya (Carica papaya), Korolla (Momordica charantia) and Mahogany (Swietenia macrophylla) were studied against the development of Ascaridia galli eggs from July 2007 to May 2008. Fresh juice, extracts and dust of leaves were tested. Fresh juice of leaves were trialed at 5%, 10% and 20% concentrations; aqueous, ethanol and methanol extracts were used at 1%, 2% and 4% concentrations and dusts of leaves were applied at 10% and 20% concentration. Among the trials, 4% of methanol extracts of papaya showed the highest efficacy (92.86%) followed by 4% ethanol extract of papaya (92%). Among the selected plants and in all three concentrations of fresh juice of leave, Bishkatali (88.46% at 20% conc.) was the highest effective plant against the development of A. galli eggs. Papaya showed the highest efficacy (71.42%) in 1% aqueous solution, but bishkatali was found as the best (73.33% and 83.33% respectively) in 2% and 4% concentration of ethanol extract of the five selected plants. In vitro screening of 5 plants with ethanol extract revealed that papaya was the highest efficacious plant (92% at 4% conc.) against development of A. galli eggs. Among the plants, in all concentrations of methanol extract of leaves, papaya was observed as best plant (92.86%, 88% and 78.95% at 4%, 2% and 1% of conc. respectively) followed by bishkatali (80% and 75% at 4% and 2% of conc. respectively) and neem (78.57% and 73.08% at 4% and 2% conc. respectively). In two concentrations of dust of leaves, bishkatali was observed as the effective plant (75% at 20% and 73.33% at 10% conc.) among the five plants. The present study suggests that dust of bishkatali leaves can be used with litter for inhibition of development of A. galli eggs and fresh juice and extract of bishkatali, neem and papaya may be impregnated in litter and used after sun dry. Key words: In vitro efficacy, indigenous plants, development, Ascaridia galli eggs doi: 10.3329/bjvm.v6i2.2329 Bangl. J. Vet. Med. (2008). 6 (2): 159-167