Ruminoreticulum bypass in goats and its possible effect on the efficacy of oxfendazole against resistant gastrointestinal parasites

Ruminoreticulum bypass was observed in 9–12-month old Angora goats using video-taped fluoroscopy. For experimental purposes, ruminoreticulum bypass was stimulated by yarding animals for 19–24 h before drenching, or by yarding and oral premedication with 2% cobalt sulphate solution. When bypass occurred, 50–100% of the drench was deposited in the abomasum. Ruminoreticulum bypass had no apparent effect on the faecal egg count reduction of benzimidazole resistant Ostertagia spp. following drenching with a standard dose of 5 mg/kg of oxfendazole, although the low frequency of bypass prevented any firm conclusions from being made. The importance of ruminoreticulum bypass to the efficacy of benzimidazole anthelmintics in goats may have been overemphasised.     

Establishment of a robotic,high-throughput platform for the specific diagnosis of gastrointestinal nematode infections in sheep

The accurate diagnosis of strongylid nematode infections is central to investigating their epidemiology and for parasite control. To overcome major limitations in sensitivity or specificity of traditional methods, including faecal egg count (FEC) and/or larval culture (LC), we evaluated and established a semi-automated, high throughput multiplexed-tandem PCR (MT-PCR) platform for the diagnosis of gastrointestinal strongylid nematode infections in sheep, and established its diagnostic sensitivity (100%) and specificity (87.5%) based on the testing of 100 faecal DNA samples from helminth-free sheep and 30 samples from sheep with infections confirmed by necropsy. Subsequently, the platform was employed to test 219 faecal samples from sheep with naturally acquired infections from various geographical localities within Australia and the results compared with those from conventional LC using 139 of the 219 samples. The results obtained using both MT-PCR and LC correlated significantly for most nematodes examined, but revealed that Oesophagostomum venulosum and Chabertia ovina (parasites of the large intestine) were significantly under-represented in the LC results. The results showed that Trichostrongylus spp. (87%), Teladorsagia circumcincta (80%) and Haemonchus contortus (67%) had the highest prevalences, followed by O. venulosum (51%) and C. ovina (12%). The molecular-diagnostic platform established can be used for species- or genus-specific diagnosis of patent nematode infections within 24 h (compared with 7–10 days for LC), and is a sensitive and cost effective tool for routine application in research and service laboratories.     

Characterization of immune responses against gastrointestinal nematodes in weaned lambs grazing willow fodder blocks

A 131-day rotational grazing experiment was conducted in the summer autumn of 2007/2008 to compare effects of feeding condensed tannin (CT)-containing willow (Salix spp.) fodder blocks (i.e., silvopastoral system) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) control pasture upon the immune response to gastrointestinal nematode parasite infection in Romney weaned lambs. Groups of lambs (n = 40) were allocated to either willow fodder blocks or control pasture; half of each group (n = 20) were regularly-drenched with anthelmintic at approximately 21 day intervals, whilst the remaining 20 weaned lambs were not drenched unless pre-determined faecal nematode egg counts (FEC) were reached, when all weaned lambs in that group were drenched with anthelmintic (i.e., trigger-drenching). Metabolizable energy and CT concentrations were higher in willow fodder versus pasture herbages. Weaned lambs grazing willow fodder blocks had lower live weight gain (92 g/day) and carcass weight (14.4 kg) than those grazing control pasture (134 g; 15.3 kg), with no effect of anthelmintic drenching. Regular anthelmintic treatment maintained similar and low FEC up to day 82, which then increased, whilst trigger-drenched lambs grazing willow fodder blocks had higher FEC than lambs grazing control pasture on three out of eight occasions. As judged by faecal larval cultures, grazing willow fodder blocks reduced the relative proportions of abomasal-dwelling parasites (Haemonchus contortus and Teladorsagia spp.). Trigger-drenched willow fodder block-fed sheep had higher platelet, eosinophil, total white blood cell and lymphocyte counts, greater CD21⁺ and greater γδ (Gamma Delta) TCR⁺ (T cell receptor) lymphocyte subsets than control pasture-fed sheep, and higher plasma levels of Immunoglobulin A (IgA) specific for carbohydrate larval antigen (CarLa) on day 105 (P<0.001). None of these parameters were affected by grazing treatment in regularly-drenched lambs. Higher immunological measurements in trigger-drenched lambs grazing willow fodder blocks could be due to higher larval intake and/or to the effects of secondary compounds in willow fodder blocks priming the immune system. Further research is required to separate these effects.     

Nematode resistance to ivermectin (630 and 700 μg/kg) in cattle from the Southeast and South of Brazil

Two high doses of ivermectin (630 μg/kg and 700 μg/kg) that are sold commercially in Brazil were evaluated in dose-and-slaughter trials with 144 naturally nematode-infected cattle from eight regions within the states of Minas Gerias, São Paulo and Rio Grande do Sul in Brazil. Treatment groups were based on fecal egg counts 1, 2, and 3 days before treatment; all animals studied had a minimum egg count of at least 500 eggs per gram of feces (EPG). Post-mortem analyses were conducted on day 14. The highest levels of resistance to ivermectin were found for Haemonchus placei, Cooperia punctata and Oesophagostomum radiatum; all populations of H. placei were resistant to the 630 μg/kg dose, and 67% were resistant to 700 μg/kg; 86% of C. punctata were resistant to the 630 μg/kg dose, and 33% were resistant to 700 μg/kg. A combined analysis revealed that 57% of O. radiatum were resistant to the lower dose of ivermectin. H. placei, C. punctata and O. radiatum, in order, were the nematode populations with the highest indices of resistance, whereas Trichostrongylus axei was the most susceptible to 630 and 700 μg/kg dosages of ivermectin. The results of helminthic resistance to ivermectin for different populations of H. placei and C. punctata described in the present study support previous literature data, in which a small decrease in the average parasitic burden of C. punctata and a consequent increase of H. placei were observed in cattle from the Southeast, South and Center-West regions of Brazil.     

Prevalence and loads of gastrointestinal parasites of goats in the communal areas of the Eastern Cape Province of South Africa

A longitudinal survey was conducted to determine the prevalence and loads of gastrointestinal parasites in goats raised by communal farmers of Qaukeni (QA) and Nkosana (NK) communities of Eastern Cape Province of South Africa between June 2007 and April 2008. One hundred and seventy one goats were weighed and had faecal samples collected from their recta in four seasons; cold-dry, hot-dry, hot-wet and the post-rainy seasons. The samples were examined by the modified McMaster technique for nematode egg types. Goats in QA weighed more (P < 0.05) than those in NK in the post-rainy, cold-dry and hot-dry seasons. However, in the hot-wet season, goats in NK had higher (P < 0.05) weights than those in QA. The most frequently detected gastrointestinal eggs were the strongyle egg type (68.4 ± 8.49 in QA and 96.1 ± 12.01 in NK), followed by coccidial oocysts (53.3 ± 8.76 in QA and 68.8 ± 8.00 in NK). The other identified nematodes were Strongyloides and Trichostrongylus egg types. Higher loads (P < 0.05) of strongyle eggs were observed in the hot-wet and post-rainy seasons, whilst the other egg types showed a peak in the hot-wet season. Strongyle egg counts were higher (P < 0.05) in NK compared to QA. The results indicate that strongyles are the major gastrointestinal egg types negatively affecting body weights of goats.     

Genetic parameters of animal traits associated with coccidian and nematode parasite load and growth in Scottish Blackface sheep

Gastrointestinal parasitism is a global problem for grazing ruminants which can be addressed in a sustainable way through breeding animals to be more resistant to disease. This study estimates the genetic parameters of common and new disease phenotypes associated with natural nematode and coccidian infection in Scottish Blackface sheep to underpin future genetic improvement strategies for parasite control. Data on faecal egg counts (FEC) from different species of strongyle parasites and faecal oocyst counts (FOC) from coccidian parasites were collected on 3-month-old lambs together with a faecal soiling score in the breech area dagginess (DAG) and live weight (LWT). Faecal count data were obtained for Strongyles (FEC_S), Nematodirus (FEC_N) and Coccidia (FOC). Data from 3 731 lambs sampled between 2011 and 2017 were included. Faecal egg counts and DAG records were log-transformed prior to analysis. Data were analysed using linear mixed models. Average age at sampling was 92 days with a mean LWT of 24.5 kg. Faecal soiling was not evident in 69% of lambs. Coccidia were the most prevalent parasite (99.5%), while Strongyles and Nematodirus had a prevalence of 95.4% and 72.7%, respectively. Heritability estimates (± SE) were 0.16 ± 0.03, 0.17 ± 0.03, 0.09 ± 0.03, 0.09 ± 0.03 and 0.33 ± 0.04 for FEC_S, FEC_N, FOC, DAG and LWT, respectively. Strongyles faecal egg count had a strong and positive genetic correlation with FEC_N (0.74 ± 0.09) and a moderate positive correlation with FOC (0.39 ± 0.15) while DAG was negatively genetically correlated with LWT (− 0.33 ± 0.15). The significant positive genetic correlations between FEC_S, FEC_N and FOC at 3 months of age show that co-selection of sheep for resistance to these different parasites is feasible. Selection for increased resistance to parasite infection is not expected to adversely affect live BW, as no significant antagonistic genetic correlations were found between LWT and FEC. There were significant antagonistic phenotypic and genetic relationships between DAG and LWT being − 0.19 ± 0.02 and − 0.33 ± 0.15, respectively, indicating that the expression of the manifestation of disease in lambs may be a more meaningful indicator of the impact of parasite burden on productivity.     

Persistent efficacy of long-acting moxidectin for control of trichostrongylid infections of sheep

The objective was to evaluate long-acting moxidectin (Cydectin^® 2% LA for sheep) against trichostrongylids in sheep. We performed a blocked, parallel, controlled clinical trial. We included 45 ewe-lambs, allocated into treated (n = 30, 1.0 mg moxidectin per kg bw, subcutaneously at base of ear on D 0) or controls (n = 15). Animals had been naturally infected (pre-treatment geometric mean epg counts: 233 and 249, respectively) and throughout the study grazed at the same pasture. Fortnightly, we collected faecal samples and performed established parasitological techniques (epg counts, coprocultures). We used analysis of covariance for post-treatment results, using pre-treatment counts as covariate, treatment as fixed effect, block as random effect. Geometric mean epg counts in treated animals were 0 up to D 112, 1 on D 126, 4 on D 140 and 13 on D 161. Respective figures for controls were 369–820 up to D 140 and 168 on D 161 (p < 0.05). Persistent efficacy (>90%) was 140 d for Teladorsagia, 119 d for Haemonchus and 115 d for Trichostrongylus. This is the first reported clinical trial of efficacy of long-acting moxidectin in sheep in Europe. Cydectin 2% LA was found to be effective against trichostrongylids of sheep. The particularly long persistent efficacy can provide new possibilities in formulating anthelmintic programs for sheep.     

Distribution of nematode larvae of sheep in tropical pasture plants

The aim of this work was to study the dynamics of parasitic nematode larvae of sheep (third larval stage), in tropical forage species. The experiment was composed of two different dry matter yield for each plant species, Pensacola grass (Paspalum saurae) and Aruana grass (Panicum maximum). The animals in the experiment were 28 Suffolk lambs that were 6–8 months old. Lambs were left in a naturally contaminated pasture for 86 days. A randomized design was adopted, collection of pasture was made every 15 days, separated into upper and lower portions and made larval enumeration. Lambs were evaluated by faecal egg count (FEC) to monitoring worm infection. The number of parasite larvae in both forages was similar (p > 0.05). However, higher (p < 0.05) infestation by helminth larvae in forage with lower dry matter yield, was observed in the upper portion of both plants studied. Animals with lower forage yield, for both forages, presented superior averages (p < 0.05) of FEC compared to higher forage yield pasture. Lambs grazing on Pensacola grass, with lower dry matter yield, showed increasing FECs over time. Lambs maintained on the pasture with higher yield of dry matter (Aruana) showed decreasing FECs over time. Similar results were observed when each pasture type was analysed for larval contamination. Epidemiologic and management implications are discussed in this work.     

Concurrence of Eimeria and helminth parasitic infections in West African Dwarf kids in Ghana

The sequence of appearance of Eimeria and helminths, in 20 West African Dwarf kids from birth and the pattern of oocyst and strongyle worm egg output for 1.5 years are described. Eimeria oocysts appeared early about 20 days after birth and oocyst output in some kids reached 2.7 million oocysts per gram (opg) of faeces about 39 days after birth and showed a group mean oocyst output of 443,540 opg in the second month but this declined further to 23,840 opg after 5.5 months. Eimeria arloingi (20.50%), Eimeria ninakohlyakimovae (17.02%), Eimeria alijevi (15.07%), Eimeria caprina (12.65%), Eimeria jolchijevi (11.42%), Eimeria apsheronica (8.70%), Eimeria pallida (5.31%), Eimeria caprovina (3.29%), Eimeria hirci (3.20%) and Eimeria christenseni (2.84%) were seen in a descending order of prevalence. Strongyle worm ova were seen 53 days after birth and peaked soon after the fall in Eimeria oocyst output but thereafter fluctuated. The eggs of cestode, Moniezia spp. appeared later but was transient. Both oocyst and worm egg output declined and were almost absent when the kids were about 1 year old. Faecal larval cultures were made and the L₃s identified with the dominant ones being Haemonchus spp. and Trichostrongylus spp. Sixty percent of the kids in this study died when they were 7 months old and a total of 70% of the kids had died before they were 1 year old.     

A survey for Echinococcus spp. of carnivores in six wildlife conservation areas in Kenya

To investigate the presence of Echinococcus spp. in wild mammals of Kenya, 832 faecal samples from wild carnivores (lions, leopards, spotted hyenas, wild dogs and silver-backed jackals) were collected in six different conservation areas of Kenya (Meru, Nairobi, Tsavo West and Tsavo East National Parks, Samburu and Maasai Mara National Reserves). Taeniid eggs were found in 120 samples (14.4%). In total, 1160 eggs were isolated and further analysed using RFLP-PCR of the nad1 gene and sequencing. 38 of these samples contained eggs of Echinococcus spp., which were identified as either Echinococcus felidis (n = 27) or Echinococcus granulosus sensu stricto (n = 12); one sample contained eggs from both taxa. E. felidis was found in faeces from lions (n = 20) and hyenas (n = 5) while E. granulosus in faeces from lions (n = 8), leopards (n = 1) and hyenas (n = 3). The host species for two samples containing E. felidis could not be identified with certainty. As the majority of isolated eggs could not be analysed with the methods used (no amplification), we do not attempt to give estimates of faecal prevalences. Both taxa of Echinococcus were found in all conservation areas except Meru (only E. felidis) and Tsavo West (only E. granulosus). Host species identification for environmental faecal samples, based on field signs, was found to be unreliable. All samples with taeniid eggs were subjected to a confirmatory host species RLFP-PCR of the cytochrome B gene. 60% had been correctly identified in the field. Frequently, hyena faeces were mistaken for lion and vice versa, and none of the samples from jackals and wild dogs could be confirmed in the tested sub-sample. This is the first molecular study on the distribution of Echinococcus spp. in Kenyan wildlife. The presence of E. felidis is confirmed for lions and newly reported for spotted hyenas. Lions and hyenas are newly recognized hosts for E. granulosus s.s., while the role of leopards remains uncertain. These data provide the basis for further studies on the lifecycles and the possible link between wild and domestic cycles of cystic echinococcosis in eastern Africa.     

The effect of heather supplementation on gastrointestinal nematode infections and performance in Cashmere and local Celtiberic goats on pasture

A study was performed on 48 adult dry goats (16 local Celtiberic and 32 Cashmere does) at pasture and naturally infected with gastrointestinal nematodes to investigate the effects of heather supplementation on faecal egg count(s) (FEC) and live weight changes. The experiment was carried out in a mountain area in the north-west of Spain from June to November in 2003. Two plots of 10,550 and 9,050 m² with perennial ryegrass/white clover (Lolium perenne/Trifolium repens) pastures were established and a total of 24 goats (8 local Celtiberic does and 16 Cashmere does) were randomly allocated to each plot. The trial consisted of comparing live weight changes and FECs in goats fed heather supplement (treated group) or not (control group). A supplement of freshly cut heather was offered ad libitum to the treated group every 3 days in the morning. Cashmere does showed a significantly (P < 0.001) lower live weight decrease than the Celtiberic goats. The goats supplemented with heather showed a lower FEC than compared controls and this effect was significant (P < 0.05) in August and in the following controls (September, October and November). Two goats died before November in the control group. In conclusion, it seems that the availability of heather reduces the FEC in goats grazing ryegrass/white clover pastures and tends to improve their live weights.     

Occurrence of cestodes and comparative efficacy of Typha angustata and sulphadimidine against cestodes in Columba livia domestica (Domestic Pigeon)

The occurrence of intestinal parasites of Columba livia domestica has been on the increase, leading to high economic and production losses with more fatal cases. This study was designed to investigate the prevalence of cestodes in pigeons and determine the efficacy of Typha angustata extract and sulphadimidine against these cestodes in the domestic pigeon. A total of 30 pigeons were examined. 18 (60%) pigeons were found infected with only one type of cestode species (Raillietina spp.). The difference in prevalence between males and females was statistically significant (χ² = 8.167, p = 0.004). The mean EPG count in group A (treated with T. angustata extract) before treatment and after treatment was 176 ± 4.33 and 155 ± 4.24, respectively. In group B (treated with sulphadimidine), the mean EPG calculated before treatment and after treatment was 184 ± 6.74 and 35 ± 3.53, respectively. The efficacy at day 28 of T. angustata and Sulphadimidine was 11.93% and 80.97%, respectively. It was concluded on the basis of the EPG and efficacy data that T. angustata extract had low efficacy against raillietiniasis, while as sulphadimidine, which is also used before to treat different intestinal parasites, had a good efficacy against raillietiniasis. Further studies are required to know the prevalence of other gastrointestinal parasites in pigeons and efficacy of different medicinal plants against such parasites.     

In vitro and in vivo effects of the phytohormone inhibitor fluridone against Neospora caninum infection

Neospora caninum causes abortion and stillbirth in cattle. Identification of effective drugs against this parasite remains a challenge. Previous studies have suggested that disruption of abscisic acid (ABA)-mediated signaling in apicomplexan parasites such as Toxoplasma gondii offers a new drug target. In this study, the ABA inhibitor, fluridone (FLU), was evaluated for its action against N. caninum. Production of endogenous ABA within N. caninum was confirmed by ultra-performance liquid chromatography–tandem quadruple mass spectrometry. Subsequently, FLU treatment efficacy was assessed using in vitro. Results revealed that FLU inhibited the growth of N. caninum and T. gondii in vitro (IC₅₀ 143.1 ± 43.96 μM and 330.6 ± 52.38 μM, respectively). However, FLU did not affect parasite replication at 24 h post-infection, but inhibited egress of N. caninum thereafter. To evaluate the effect of FLU in vivo, N. caninum-infected mice were treated with FLU for 15 days. FLU treatment appeared to ameliorate acute neosporosis induced by lethal parasite challenge. Together, our data shows that ABA might control egress in N. caninum. Therefore, FLU has potential as a candidate drug for the treatment of acute neosporosis.     

Microbial processes and bacterial populations associated to anaerobic treatment of sulfate-rich wastewater

A pilot-scale (1.2 m³) anaerobic sequencing batch biofilm reactor (ASBBR) containing mineral coal for biomass attachment was fed with sulfate-rich wastewater at increasing sulfate concentrations. Ethanol was used as the main organic source. Tested COD/sulfate ratios were of 1.8 and 1.5 for sulfate loading rates of 0.65–1.90 kgSO₄²⁻/cycle (48 h-cycle) or of 1.0 in the trial with 3.0 gSO₄²⁻ l⁻¹. Sulfate removal efficiencies observed in all trials were as high as 99%. Molecular inventories indicated a shift on the microbial composition and a decrease on species diversity with the increase of sulfate concentration. Beta-proteobacteria species affiliated with Aminomonas spp. and Thermanaerovibrio spp. predominated at 1.0 gSO₄²⁻ l⁻¹. At higher sulfate concentrations the predominant bacterial group was Delta-proteobacteria mainly Desulfovibrio spp. and Desulfomicrobium spp. at 2.0 gSO₄²⁻ l⁻¹, whereas Desulfurella spp. and Coprothermobacter spp. predominated at 3.0 gSO₄²⁻ l⁻¹. These organisms have been commonly associated with sulfate reduction producing acetate, sulfide and sulfur. Methanogenic archaea (Methanosaeta spp.) was found at 1.0 and 2.0 gSO₄²⁻ l⁻¹. Additionally, a simplified mathematical model was used to infer on metabolic pathways of the biomass involved in sulfate reduction.     

Attempts to vaccinate ewes and their lambs against natural infection with Haemonchus contortus in a tropical environment

A vaccine containing integral membrane glycoproteins from the intestine of Haemonchus contortus was evaluated in three groups of grazing sheep each containing 13 ewes and their 16 lambs naturally infected with gastrointestinal nematodes. Two groups were vaccinated with either 5 or 50 μg of the antigen per immunisation, while the third, the control group, received adjuvant alone. The sheep were immunised six times at 3 week intervals, partly because the vaccine antigens are hidden and thus no immunological boost would be delivered by subsequent infection and partly because the level of Haemonchus spp. challenge was expected to be high. The vaccinated ewes, first immunised approximately 1 month before lambing, showed a circulating antibody response but no signs of reduced anaemia or Haemonchus spp. egg counts, compared with control ewes. Several ewes with severe haemonchosis in all three groups had to be given precautionary treatment with anthelmintic drugs. In contrast, vaccinating their lambs with either 5 or 50 μg of the antigen per immunisation resulted in 10 fold higher antibody titres. In the case of the lower antigen dose this was associated with significantly less anaemia, 72% reduction in the overall number of Haemonchus spp. eggs produced and significantly fewer worms compared with control lambs. It is hypothesised that the heavily pregnant or lactating ewes did not have sufficient physiological reserves to mount a protective response following vaccination in the tropical weather and high challenge conditions that prevailed. Nevertheless, the vaccine could afford useful protection for lambs against H. contortus.     

Seasonal dynamics and spatial distribution of epiphytic dinoflagellates in Peter the Great Bay (Sea of Japan) with special emphasis on Ostreopsis species

Studies of epiphytic dinoflagellates in Peter the Great Bay, Sea of Japan in 2008–2011 revealed the presence of 13 species. Five of the species are known as potentially toxic: Amphidinium carterae, A. operculatum, Ostreopsis cf. ovata, O. cf. siamensis and Prorocentrum lima. The maximum species richness and abundance of epiphytic dinoflagellates were observed in autumn (from September to October). Ostreopsis spp. were most widely distributed and predominated, amounting to 99% of the total density of dinoflagellates. Multi-year seasonal dynamics of Ostreopsis spp. in Peter the Great Bay showed that these cells appear as epiphyton in August after maximum warming of surface waters (22–24 °С) and disappear in early November, when the water temperature decreases below 7 °С. Ostreopsis spp. proliferation occurred in September, when the water temperature was 17.2–21.0 °C. The highest densities of Ostreopsis spp. were recorded on September 9, 2010 on the rhodophyte Neorhodomela aculeata – 230 × 10³ cells g⁻¹ DW or 52 × 10³ cells g⁻¹ FW. The spatial distribution of epiphytic dinoflagellates was investigated in the near-shore areas of Peter the Great Bay during the second half of September 2010 to evaluate the role of hydrodynamic conditions. Epiphytic dinoflagellates were not found in sheltered sites having weak mixing hydrodynamics. However, the abundances of Ostreopsis spp. were significantly higher at sites having moderate turbulence compared to biotopes experiencing strong wave action. Densities of Ostreopsis spp. were not significantly different on macrophytes with branched thallus of all taxonomic divisions. However, the average cell densities of Ostreopsis spp. on green algae with branched thallus were significantly higher than on green algae having laminar thallus.     

Antioxidant effects of clove bud (Syzygium aromaticum) extract used with different extenders on ram spermatozoa during cryopreservation

Clove bud (Syzygium aromaticum) extract was added at concentrations of 0, 35, 75, and 115 μg/ml to ovine semen extenders in order to investigate the antioxidant activities of clove bud extract and its effects on semen quality parameters after cryopreservation of ram spermatozoa. The basic extender was composed of Tris, egg yolk, and glycerol. Two other extenders were prepared by substitution of egg yolk with either LDL or egg yolk + SDS. The DPPH inhibition test was employed to assess the antioxidant activity of clove bud extract. Results showed that, compared to vitamin E, clove bud extract had a higher antioxidant activity. Better sperm motility and movement characteristics (P < 0.05) were observed in the semen diluted with medium containing egg yolk + SDS than in that containing egg yolk and LDL. Progressive motility and movement characteristics of the sperm were significantly improved (P < 0.05) by adding 35 and/or 75 μg/ml of clove bud extract to semen extenders. Sperm viability and plasma membrane integrity were also higher (P < 0.05) in the semen exposed to medium containing egg yolk + SDS and 75 μg of clove buds extract after cryopreservation processes. Higher levels of clove bud extract, however, had adverse effects on all the sperm quality parameters and significantly reduced (P < 0.05) the motility, movement parameters, viability, and plasma membrane integrity of ovine sperm. It was concluded that the clove bud extract had an antioxidant potential that makes it useful for addition to semen extenders and that the best results are obtained with a maximum clove bud extract of 75 μg/ml. Moreover, the combination of egg yolk and a detergent was found to improve sperm quality after the cooling and freeze–thawing processes.     

A comparative evaluation of efficacy of chemotherapy,immunotherapy and immunochemotherapy in visceral leishmaniasis-an experimental study

Visceral leishmaniasis (VL) represents the second most challenging infectious disease worldwide, leading to nearly 500,000 new cases and 60,000 deaths annually. Ninety per cent of VL cases occur in five countries namely Bangladesh, India, Nepal, Sudan and Brazil. No licensed vaccine is available till date against any form of leishmaniasis. High toxicity and increasing resistance to the current chemotherapeutic regimens have further complicated the situation in VL endemic regions of the world. To combat this situation, immunochemotherapy can provide a solution. In the present study, an attempt has been made to assess the in vivo antileishmanial efficacy of chemotherapy, immunotherapy and immunochemotherapy with the use of a first generation antigen Killed Leishmania donovani (KLD) along with a standard drug sodium stibogluconate (SSG) and a newly tested antileishmanial cisplatin. Inbred BALB/c mice were infected with 10⁷ promastigotes/0.1 ml of Leishmania donovani. A month after infection, these animals were given specific immunotherapy (KLD/KLD + MPL-A) or chemotherapy (SSG/cisplatin) or immunochemotherapy (SSG + KLD/SSG + KLD + MPL-A/cisplatin + KLD/cisplatin + KLD + MPL-A). Animals were sacrificed on 1, 15 and 30^th day post treatment. The efficacy of these combinations was assessed in terms of parasite load and by immunological investigations. Infected mice and normal mice served as controls. Results showed that combination of drug and KLD significantly reduced the parasite burden, enhanced the DTH (Delayed Type Hypersensitivity) responses, showed increased levels of IgG2a and decreased levels of IgG1 as compared to mice given chemotherapy or immunotherapy alone. Further maximum protection was provided by SSG + KLD + MPL-A and it was most effective as depicted by 98.5% reduction in parasite load, a potent increase in IFN-γ levels and a significant decrease in IL-10 and IL-4 levels thus skewing the immune response towards Th1 type. Hence, immunochemotherapy is more effective in control of VL in comparison to chemotherapy or immunotherapy.