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A cross sectional study was carried out during the dry season (between June and August
2014) to establish the status of helminth infestation in nine traditionally managed small
ruminant flocks in Mlandizi village of Melela ward in Mvomero district of the Morgoro
region. A longitudinal study was thereafter implemented from August 2014 to January
2015 to determine the influence of Haemonchus spp. target Barbevax® vaccine on
gastrointestinal parasite burdens in traditional sheep and goats using Barbevax® vaccine.
Animals were visited after every 14 days for up to the 19th week. During each visit blood
and faecal samples were collected. Vaccination was done four times on days 0, 28, 56 and
98. The vaccine was administered subcutaneously using 1 ml for each animal to be
vaccinated. All the study flocks, which were communally grazed and purposively
selected, had varying numbers of sheep and goats. The study involved 131 goats and 118
sheep, which were screened for helminth eggs and then the faecal samples, were cultured
to recover helminth larvae (L3) which were identified using morphological features. Out
of the animals screened, 54.2% and 67.8% of the goats and sheep examined respectively
were positive for helminth infestation. The most prevalent helminth species detected was
Haemonchus spp. (50.7%). Others were Trichostrongylus spp. (29%), Oesophagostomum
spp. (16.4%), Cooperia spp. (5.9%) and Strongyloides spp. (3.4%). Results indicated that
female sheep and goats had greater packed cell volume (PCV) than males with a
significant difference (P< 0.05) and with ages 3, 6, 7 and 12 months (P< 0.05). At day 56
significant difference was observed between vaccinates and control animals (P< 0.05).
The observation was that males had their EPGs going down gradually with a significant
difference among males (P< 0.05). There was a significant difference in EPGs (P<0.05),
for days 14 and 42. The mean EPG of males were relatively higher than those of females
with a significant difference for both sexes (p<0.05). It was observed further that young animals (age 2-5 months) had relatively higher EPGs than older animals 6+ months. The
mean number of larvae of Haemonchus between vaccinates and controls goats was
statistically significant (p<0.05) for ages 3 and 9 months. No differences in either total or
Haemonchus specific egg counts were observed between vaccinates and controls after
third vaccination in either sheep or goats. Helminth infestation was shown to be a problem
and haemochosis being the most prevalent. The potential of the vaccine efficacy in above
associated risk factors is to be further studied in different environments under different
infection rates of H.contortus. Futhermore, the studies to analyse plasma antibodies
should be done to ascertain immune response after vaccination. |
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