G. Saritha, B. Shobhamani, B. Sreedevi

Animal Science Reporter, Volume 8, Issue 3, July, 2014
SERO-PREVALENCE OF PESTE DES PETITS RUMINANTS IN PASTORAL SMALL
RUMINANTS WITH SPECIAL REFERENCE ON SENSITIVITY TO AGE AND AGROCLIMATIC ZONE*
G. Saritha1, B. Shobhamani2, B. Sreedevi3
ABSTRACT
Peste des petits ruminants (PPR), an economically devastating viral disease of
domestic small ruminants is extremely endemic in southern peninsular states.
The epidemic cycle of PPR virus can be blocked by detection and elimination of
gullible animals through sero-surveillance. This paper deciphers the seroprevalence of PPR in sheep and goats in different age groups and in different agroclimatic zones of Andhra Pradesh, India. The study was conducted on 803 sera
samples collected from 398 sheep and 405 goats of different age groups, viz., young
(4-12 months), adults (13-48 months) and old (> 48 months) of three agro-climatic
zones, viz., Southern Zone (AP-3), Northern Telangana Zone (AP-4), and Scarce
rain fall Zone of Rayalseema (AP-6) of Andhra Pradesh from non-immunized
pastoral sheep and goat flocks of 50 farmers, for detection of antibodies against
PPR virus (PPRV) by competitive enzyme linked immuno-sorbent assay (c-ELISA)
method. The overall incidence of PPR in sheep and goats was 67.87% in the study
area. The incidence was higher in goats (70.37%) than in sheep (65.32%), but the
difference was non-significant (P0.05). There was significant (P0.05) difference
in sero-prevalence of PPR in small ruminants (sheep & goat in concert) between
the agro-climatic zones, but the difference between sheep and goats in each of the
zones was non-significant (P0.05). The incidence in AP-3 (75.27%) was
significantly (P0.05) higher than in AP-4 (49.25%) and AP-6 (64.09%), and the
incidence in AP-6 was significantly (P0.05) higher than AP-4. The incidence in
adults (80.65%) was significantly (P0.05) higher than in young (67.83%) and
older (44.15%) animals. The difference between the latter two was also significant
(P0.05). The study tends to conclude that the effect of agro-climatic zone on seroprevalence of PPR in the study area was positive but ambivalent, which needs to
be defined, and the younger animals  48 months) should be targeted for focused
vaccination in PPR sensitive zones to block the epidemic cycle of the virus.
KEY WORDS
Andhra Pradesh, c-ELISA, Goat, PPR, Sero-prevalence, Sheep
Author attribution: 1Assistant Professor, 2 Professor, Department of Veterinary Medicine, 3 Professor,
Department of Veterinary Microbiology, College of Veterinary Science, Sri Venkateswara Veterinary University,
Tirupati, Andhra Pradesh, India-517502. 1Corresponding author: [email protected] *Part of MVSc
thesis (Sri Venkateswara Veterinary University) of the first author. Date of Receipt: 20/03/2013, Acceptance:
20/03/2014. pp. 103-107.
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Animal Science Reporter, Volume 8, Issue 3, July, 2014
INTRODUCTION
Peste des petits ruminants (PPR) in sheep
and goats caused by PPR virus is an acute,
highly contagious, and trans-boundary
febrile viral disease, with exceptionally high
morbidity and high mortality. It is reported
age groups, collected from 50 flocks of
farmers from three agro-climatic zones of
Andhra Pradesh (Figure-1, Table-1) were
used for this study. Apparently healthy and
diarrhoeic animals with acute respiratory
distress were included in the study.
that goats are more susceptible than sheep
One millilitre of blood was collected from the
(Balamurugan et al., 2012) and younger
jugular vein of each of the animals in test
animals in both the species are more
tube. After the collection of blood, the test
vulnerable than the adults (Singh et al., 2009).
tubes were kept in slanting position for
PPR is endemic in several states of India, and
is extensively endemic in southern
peninsular states (Raghavendra et al., 2008)
clotting of blood at room temperature, and
then the test tubes were kept at refrigeration
temperature for two hours for analysis.
and sero-positivity in apparently healthy
The serum samples were assayed for the
flocks (Balamurugan et al., 2014) is a caveat
presence of antibodies to PPRV by
to initiate state sponsored comprehensive
competitive enzyme-linked immunosorbent
steps to contain PPR through identification
assay (c-ELISA) using a kit developed at the
of the vulnerable animals through sero-
Indian Veterinary Research Institute,
surveillance and focused vaccination in
Mukteswar, India. The competitive ELISA (c-
sensitive areas to block the epidemic cycle of
ELISA) test is based on inhibition of the
the virus (Singh, 2011).
binding of monoclonal antibody to antigen
The variation in endemicity of the disease in
southern peninsular states has been
attributed to agro-climatic condition and
trans-border migration of the animals
(Raghavendra et al., 2008). This paper
examines the variability in sero-prevalence
of PPR in three different agro-climatic zones
of Andhra Pradesh in non-immunized
pastoral sheep and goat flocks of the farmers.
in the presence of PPR antibody in the sera.
A monoclonal antibody (MAb) designated
4B11 that is directed against a neutralising
epitope of the haemagglutinin (HA) protein
of PPRV is employed in the kit. The test was
performed as per the protocol outlined in the
user manual supplied with the kit. Results
were read at 492 nm in ELISA plate reader
(Multiskan plus, Lab System) using EDI
software.
MATERIALS AND METHODS
The differences between the sero-positive
The serum samples of 803 unvaccinated
animals in different groups were compared
animals (Sheep: 398, Goat: 405) of different
by chi-square test.
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Animal Science Reporter, Volume 8, Issue 3, July, 2014
Figure-1. Agro-climatic zones of Andhra Pradesh (Downloaded from www.google.co.in).
Table-1. Climatic condition of different agroclimatic zones.
Zone
AP-3
Maximum
Temp (°C)
33-46
Minimum
Temp (°C)
23-25
Rain fall
(mm)
700-1100
AP-4
28-34
22-23
700-900
AP-6
32-36
24-30
500-750
RESULTS AND DISCUSSION
Incidence of PPR in sheep and goat: The
sero-positivity of PPR was 67.87% in the
study area. It was higher in goats (70.37%)
than in sheep (65.32%), but the difference
was non-significant (P0.05). Our study
indicated that both sheep and goat were
equally vulnerable to PPRV, although the
incidence was higher in goats on face value.
There was no significant difference (P0.05)
between sheep and goats in different agroclimatic zones (Table-2, Figure-2).
It was contrary to the report of Raghavendra
et al. (2008), who had found significantly
(P0.05) higher incidence in sheep than in
goats, while, Balamurugan et al. (2011) and
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Animal Science Reporter, Volume 8, Issue 3, July, 2014
Balamurugan et al. (2012) had reported
higher (P0.05) incidence of PPR in goats
than in sheep. Our finding agreed with
Balamurugan et al. (2014), who had reported
non-significant (P0.05) difference between
sheep and goat. Sampling error might be
responsible for this controversial result,
rather than species-specific difference.
Incidence of PPR in different agro-climatic
zones: Comparison between different zones
(Table-2, Figure-2) indicated that the
incidence in sheep was the highest in AP-3
(74.23%) followed by AP-6 (62.06%) and AP4 (40.63%). The difference between the zones
was significant (P0.05). Comparison
between different zones in goats indicated
that it was the highest in AP-3 (76.14%)
followed by AP-6 (66.47%) and AP-4
(57.14%). The incidence in AP-4 was
significantly (P0.05) lower than in AP-3
and AP-6. The difference was nonsignificant (P0.05) between AP-3 and AP6. The incidence in sheep and goat together
was the highest in AP-3 (75.27%) followed
by AP-6 (64.09%) and AP-4 (49.25%). The
differences between the zones were
significant (P0.05).
The difference in the incidence of PPR in
different agro-climatic zones might be
attributed to differential effects of feed and
fodder availability to the animals, since small
ruminants mostly thrive on pasture and
shrubs on range (Waret-Szukta et al., 2008).
However, the possible causes of difference
in sero-prevalence of PPRV between different
agro-climatic zones were not discernible in
this maiden study.
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Table-2. Sero-prevalence of PPRV in
different agro-climatic zones of Andhra
Pradesh.
Zone
AP-3
AP-4
AP-6
Total
Sheep
74.23a1
(121/163)
40.63b1
(13/32)
62.06c1
(126/203)
65.321
(260/398)
Goat
7 6.14a1
(150/19 7)
5 7.14b1
(20/35 )
6 6.47a1
(115/17 3)
70.371
(285/40 5)
Total
7 5.27a
(27 1/360)
4 9.25b
(3 3/67)
64.09c
(24 1/376)
67.87
(54 5/803)
Note: (1) The figures are presented as percentage of
ca ses sero-positi ve for PPRV (Number of sera
positive/ Number of sera tested). (2) Fi gures
displaying different superscripts (a, b, c) in a column
and different numerical (1, 2) in a row differed at
P 0.0 5.
Figure-2. Sero-prevalence of PPR in sheep and
goat in different agro-climatic zones.
Incidence of PPR in different age-groups:
There was no significant difference (P0.05)
in sero-prevalence of PPR between sheep and
goat at different ages (Table-3, Figure-3). The
incidence in sheep and goat together was
higher in adult animals (80.65%) followed
by young (67.83%) and the older animals
(44.15%). The difference between the age
groups was significant (P0.05).
Our findings are in agreement with the
report of Mahajan et al. (2012), who had
observed that sheep and goats above 12
months of age had higher sero-prevalence of
Animal Science Reporter, Volume 8, Issue 3, July, 2014
PPR than younger animals. However, the
reduction in PPR incidence in older animals
is contrary to the observation of Waret-Szukta
et al. (2008), who had reported linear effect of
age on the sero-prevalence of PPRV, and was
the highest in older animals.
Table-3. Age wise sero-positive cases of
PPRV.
Age
4-12 m
13-48 m
> 48 m
Total
Sheep
63.38 a1
(45/71)
75.86b1
(154/203)
49.19c1
(61/124)
65.32 1
(260/398)
Goat
72.22a1
(52/72)
84.95b1
(192/226)
38.31c1
(41/107)
70.371
(285/405)
Total
67.83a
( 97/143)
80.65 b
(346/429)
44.15c
(102/231)
67.87
(545/803)
Note: (1) The figures are presented as percentage of
ca ses sero-positi ve for PPRV (Number of sera
positive/ Number of sera tested). (2) Fi gures
displaying different superscripts (a, b, c) in a column
and different numerical (1, 2) in a row differed at
P 0.0 5.
Figure-3. Sero-prevalence of PPR in sheep and
goat in different age groups.
CONCLUSION
The difference in sero-prevalence of PPR in
different agro-climatic zones indicated that
PPR control strategy should be adopted
differently for different agro-climatic zones.
The young and adult animals should be the
target groups to control PPR.
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