South Asia:
India: India has twenty-eight states and seven union
territories. The country possesses about 200 million sheep and goats
(Ministry of Agriculture, Government of India, 2009). PPR is endemic in
India and is a major threat to about 200 million small ruminant
population of the country (Dhar et al., 2002), causing an economic loss
of about 1800 million Indian rupees annually (Bhadyopadhyay, 2002).
Close contact is the most important way of transmitting the disease. It
is suspected that the infectious materials can also contaminate water,
feed troughs and bedding, turning them into additional sources of the
infection. These are however short-term sources, since the PPRV, like
its close relative the Rinderpest virus, would not be expected to
survive for a long time outside the host (Diallo, 2003). In addition to
these sources of infection movement of animals across the boundaries of
states commonly acts as source of PPR epidemics. There is no known
carrier state in PPR and the infected animal may transmit the disease
itself during the stage of incubation period. However, the PPR infected
animal’s seroconvert and become immune to PPR and RP viruses (Sudarshan
et al., 1995). Singh et al. (2004) discussed the relation of migration
of animals with that of maintenance and transmission of PPRV in nature.
The close relations between PPR outbreaks and transportation of sheep
and goats’ flocks have been reported (Boniwell, 1980; Dhand et al.,
2002; Kataria et al., 2007; Shankar et al., 1998). Migration may also
spread infection to cattle (Shaila et al., 1989).
In India, animal rearing is practiced in two major ways: one is
unorganized back yard rearing (where 5–10 sheep or goats are reared in
backyards and fed up on the agriculture byproduct) and the other is the
traditional rearing of sheep and goats by nomadic communities (where the
animals are fed on pasture lands and uncultivated or barren fields
during the course of migration). Most of the earlier studies from India
were conducted on sheep and goats of non-migratory flock (Singh et al.,
1996, 2004; Kataria et al., 2007; Bhanuprakash et al., 2008) but the
present study covered animals of both migratory and non-migratory
flocks. According to Mahajan et al. (2012), the risk of PPR is higher in
migratory flocks than in non-migratory flocks. The animals of these
migratory flocks were brought from hilly areas through different routes
after the completion of their seasonal migration to escape severe
winters. This seasonal movement of animals may increase the chance of
transmission among the migratory flocks. Moreover, in migratory flocks,
there is transportation stress, underfeeding and underlying parasitic
infection which may decrease the immunity, thereby increasing the
susceptibility of animals to disease. These facts were also supported by
the findings of other workers who reported outbreaks of PPR in migratory
herds in Himachal Pradesh (Joshi et al., 1996) and Rajasthan (Singh et
al., 1996). Similarly, Khan et al. (2007) reported higher
sero-prevalence of PPR in southern and western parts of Punjab of
Pakistan where nomadic rearing of sheep and goats was common.
The virus spreads through close contact via respiratory route. Viremia
develops 2-3 days post infection. Fine infective droplets from the
secretions and excretions of the infected animals are released into the
air (Sen et al., 2010). Transmission could also occur through
contaminated water, feed troughs and bedding (Lefèvre and Diallo, 1990).
In India, animals are allowed to share common grazing land and water
sources are risk factors. Besides, migration of animals between various
states is common especially, in the sub-Himalayan region and western dry
land areas such as Rajasthan and Gujarat (Nanda et al., 1996; Singh et
al., 2004). Mixing of these migrated populations with local population
may contribute to the disease transmission. Further, during the festival
seasons, animals are shipped to various states for meat purposes. These
unrestricted movements of animals contribute significantly to the
epidemiology of the disease. In India, the disease occurs round the year
and the maximum outbreaks reported during the winter and rainy
seasons. Therefore, vaccination just takes place prior to the onset of
rainy/ winter season. Initially, PPRV was classified in to 4 lineages
I–IV based on the F gene sequencing (Dhar et al., 2002; Shaila et al.,
1996); lineage I-III viruses were reported in several countries of
Africa and lineage IV (Asian lineage) mainly in Middle East and Asia
(Banyard et al., 2010; Dhar et al., 2002; Ozkul et al., 2002).
Currently, N gene is preferred over F gene due to its better molecular
separation (Kwiatek et al., 2007). In the recent past, many researchers
report the presence of lineage IV in African countries (Maganga et al.,
2013; Salami et al., 2014). Till now, only lineage IV viruses have been
reported in India. The PPRV goat strain isolated during the recent
outbreak at Tripura showed 99.2 to 99.6% nucleotide identities with the
Bangladesh strains (Muthuchelvan et al., 2014). The overall
epidemiological investigation confirms the transboundary transmission of
PPRV with the neighboring countries including china, Mongolia, India,
Pakistan, Bangladesh, Nepal and Afghanistan.
Pakistan: PPR was recognized
in Pakistan in early 1990s but got importance during the Participatory
Disease Surveillance (PDS) of Rinderpest Eradication Campaign. Lot of
research work has been initiated during last decade towards disease
epidemiology, risk factor recognition, laboratory diagnosis, vaccination
and demonstration of control strategies (Abubakar et al., 2015). In
Pakistan PPR is endemic, during the last decade, PPR outbreaks have
increased to an alarming level involving newer areas (Ali, 2004).
According to Zahur et al. (2011) PPRV is circulating in the small
ruminant population throughout Pakistan. As, on the basis of clinical
and serological methods, an outbreak of PPR was reported in goat flocks
of Livestock Production and Research Institute (LPRI), Bahadurnagar,
Okara, Pakistan (Khan et al., 2005). According to another report based
on observations from 50 laboratory confirmed outbreaks of PPR and
provides details of the presence or otherwise of PPRV in 427
tissue/organ samples from small ruminants in Pakistan. PPR is more
severe in goats than sheep and the frequency of disease outbreaks are
greater between the months of January to April. Spatial distribution of
PPR in various locations of Pakistan indicate that the disease pattern,
although both goats and sheep are susceptible to infection and may show
disease yet they are not always affected simultaneously, for example, in
Africa PPR is seen most commonly in goats, while in western and South
Asia sheep are usually the most noticeable victims (FAO, 1999). But if
we see the picture in Pakistan, PPR affect both goats and sheep but in
many villages, it is seen that only goats are affected usually Taylor et
al. (2005) and this concept is much supported by findings of Abubakar et
al. (2008). In different districts of Sindh province, overall PPR
seroprevalence in sheep is 49.5 % as compare to goats which is 56.3 %.
According to (Obi et al., 1983; Durojaiye et al., 1983; Abubakar et al.,
2011), most cases of PPR emerge with the start of summer season and
cases get peak during the months of April to July and then the
prevalence drop again that indicate the temporal pattern of disease Khan
et al. (2008) reported the antibody prevalence of PPRV in small
ruminants in Punjab 51.3 %. The antibodies frequency against PPRV
recorded 67.7 %, 71.1 % and 60.2 % in the months of December, January
and February and 50.7 % and 53.0 % in the months of September and
October, respectively. Less local fodder availability and poor
nutritional status of the animals may play a key role in the
transmission of disease. Zahur et al. (2011) has reported distribution
of PPRV in different districts of Pakistan that is over all 48.30 %.
Jalees et al. (2013) investigated that disease is more prevalent in
young sheep and goats than adult and predilection site of the PPRV
remained the lymph nodes.
The true sero-prevalence of PPR in Pakistan estimated to be 48.5 % (95
% CI, 46.6–50.3), and 52.9 % (95 % CI, 50.7–55.1) and 37.7 (95 %
CI, 34.4–41.0) for goats and sheep, respectively. The sheep and goats
exhibited a different seroprevalence pattern with a quite higher
prevalence in goats. The highest prevalence was recorded in animals over
2 years of age: 49.29 % of sheep and 65.94 % of goats were
seropositive for PPR (Zahur et al., 2011).
In Pakistan different vaccination programs are introduce with the live
attenuated virus belonging to Lineage I. Despite of the strict
vaccination programs and other preventive and clinical measures the PPR
outbreaks are frequent. Moreover, different type of PPR vaccines
including conventional, thermostable, recombinant and edible vaccines
has been developed and used from control/eradication of said disease
world widely (Abubakar et al. 2011; Abubakar et al. 2012; Abubakar et
al. 2015 and Odo, 2003).
Currently, vaccination is recommended in certain areas of the country.
This vaccination is based on Nig75/1, which belong to lineage II, while
field isolates from Pakistan are grouped in lineage IV. Genetic
characterization of field strains will provide foundations for
construction of vaccines from domestic strains as has recently been
practiced in India (Anees et al., 2013). While, tissue culture based
live freeze-dried PPRV (PPR 75–1) vaccine has been produced by Abbas et
al. (2012) using Vero cell line and checked for validation, safety,
sterility and efficacy. They concluded that this PPR vaccine would be an
effective tool to limit PPR disease in goats as well as to reduce
economic losses due to this disease in Pakistan. Currently, although the
PPR vaccine production capacity is present in the two places in the
country yet there is no organized PPR vaccination campaign going on.
With the current population of more than 90 million of small ruminants
and endemic situation of PPR, there is continuous threat from PPR in
terms of food security.
International authorities working on animal health (OIE and FAO) have
recognized PPR as the next target disease for control and possible
eradication from the world. So there is need of the time to have
national and regional PPR control program in the country and neighbors.
After the successful Rinderpest eradication campaign, OIE has officially
declared PPR as next candidate disease, to be eradicated. Therefore,
serious efforts have been started towards the disease understanding and
possible measures for its eradication.
Although there are some projects completed towards the progressive
control of the disease in country yet there is need to understand the
epidemiology of disease and to established a national level control and
eradication program for PPR which will link with the regional control
and eradication setup. Also there is need to have comprehensive social
economic surveys, disease hot spot recognition and identification of
role of other species like yolk, cattle, buffalo, camel and wildlife in
disease transmission. With combined efforts of local and national
authorities and political will, there is high likelihood that this
devastating disease can be controlled and eventually eradicated in near
future (Abubakar et al., 2015).
Bangladesh: In Bangladesh, PPR was first reported in goats in
1993 and since then it has become endemic in the country (Islam et al.
2001). Most of the previous PPR studies conducted in Bangladesh were
based on either serology or clinical signs except a few recent
publications with genetic characterization (Chowdhury et al. 2014;
Rahman et al. 2016). Phylogenetically, the Bangladeshi PPRV strains
belong to the PPRV lineage IV and formed a separate subgroup and these
are closely related with China-Tibet/07 and Indian/TN/VEL/2015 PPRV
isolate. The overall PPR sero-prevalence was 21% in 2008, ranging from
6% to 49% in different geographical locations/districts in Bangladesh
(Bhuiyan, 2012). A study conducted in 2009–2010 on laboratory confirmed
outbreaks of PPR in Black Bengal goats resulted in 75% and 59% flock
morbidity and mortality, respectively, with a case fatality rate of 74%
(Chowdhury et al. 2014). Approximately 84 000 veterinary clinical cases
of PPR were recorded in 2010 in Bangladesh, but it might not represent
the actual burden of the disease as they all were not laboratory
confirmed and presumptive diagnosis by veterinarians only has a moderate
predictive value (Chowdhury et al. 2014; Haider et al. 2016). Bangladesh
Livestock Research Institute (BLRI) has developed a homologous cell
culture attenuated PPR vaccine which is very potent against PPR
(Anonymous, 1999). But vaccination program has not yet covered the total
population of the country. So supportive therapy of atropine aided
antibiotic, fluid therapy and antihistaminic aided antibiotic, fluid
therapy as well as combined therapy can save the life of PPR affected
patient in field condition (Chakrabarti, 2003). According to Parvez et
al. (2014), reported prevalence of PPR in goats at Chittagong district,
Bangladesh was 8.99. The prevalence regarding PPR among kid, young and
adult goats were found to be 6.19% 11.72% and 7.52% respectively with
the significant p value (P=0.000). Thus the reported prevalence of PPR
was higher in young goats over the adults and kids agreed with the
results of Islam et al., (2012), Sarker and Islam (2011), Rahman et al.,
(2011) and Singh et al., (2004. This research also revealed that, the
highest prevalence of PPR was recorded in Black Bangle goats 10.11% in
compare to Jamunapai goats 7.44% and other cross breed goats with
significant p value (P=0.005). So that the Black Bangle goats were much
more prone to PPR in compare to Jamunapari along with other cross breed
goats similarity with the findings of Islam et al., (2012).Sarker and
Islam (2011) and Mondal et al., (1995). They observed that Black Bangle
goats were more susceptible to the PPR in compare to other goat breeds.
Prevalence of PPR in goats due to seasonal variation revealed that
highest prevalence had been seen in rainy season 11.30% in comparison
to summer 6.40% as well as winter season 8.25% with significant p
value (p=0.000). This variation might be due to different geographical
region and study period. The highest prevalence of PPR at present study
was observed in the month of August 13.75% and October 11.51% in
contrast with the findings of Sarker and Islam (2011); Abubakar et al.,
(2009) who recorded highest prevalence in the month of December
(31.68%) and January (30.34%); 32.57% in March and 19.43% in April
respectively. Results revealed that the lowest occurrence was in May
(4.09%) in contrary with this result Abubakar et al., (2009) and Sarker
& Islam (2011) who reported lowest prevalence in the month of June,
i.e., 1.71% and 9.52%, respectively. This variation might be due to
different geographical location, research period, and different
management practices. Bangladesh faces a little bad analogous issue as
existing in the neighbor’s countries like India and Pakistan regarding
the epidemiology, risk factors, pattern of disease, virus linage
distribution and future control and eradication targets. Proper
epidemiological studies are needed to be conducted in near future linked
with neighbor’s countries to control and eradicate the roots of PPR from
the region.
Nepal: PPR is epidemic disease of small ruminants which has
caused significant economic losses in Nepal (Acharya et al., 2018). In
Nepal, first outbreak of PPR was reported in 1995 (Banyard et al., 2010;
Dhar et al., 2002) from the Dhanusha, Mahottari, Bara, Sarlahi, Rauthat
and Gorkha districts (Jha et al., 2013) and about 68 districts of Nepal
have reported the PPR outbreaks covering all eco-zones and developmental
regions (DoAH, 2015). A study done by Regional Agricultural Research
Station (Goats), Bandipur under the National Agriculture Research
Council in Syangja and one other district has reported PPR as the major
infectious disease of goats and recorded 33.48% mortality,
investigative efforts were made to determine sero-prevalence of PPR in
unvaccinated goat population of Syangja and Kaski districts and
associated risk factors (Khakural, 2003). The PPR virus circulating in
different countries of Asia i.e. Nepal, India, Bhutan, China, Iran,
Iraq, Israel, Kuwait, Bangladesh, Pakistan, Saudi Arabia, Tajikistan,
Turkey is of lineage (IV) (Parida et al., 2015) however, the F and N
gene sequencing based study has shown that the virus found in Nepal,
India and Bangladesh is more closely related than virus found in rest of
the countries (Dhar et al., 2002). According to Acharya et al. (2018),
Eco zone wise distribution of PPR showed that the PPR outbreaks were
reported the highest in mountain followed by hills and the lowest in
Terai. The highest outbreaks in mountain may be due to excessive
movements of nomadic herd of sheep and goat, common pasture, low vaccine
coverage in mountain whilst in hill region due to geographic difficulty
and low sero-conversion of vaccine. Hence, strategic vaccination
campaigns, proper biosecurity, movement control, risk analysis and early
diagnosis need to be implemented for the control of PPR in the country
and also do the same strategies for the region. The above studies
justify the regional links of virus transmission, temporal and spatial
pattern of disease distribution in the region, virus lineage
distribution and other complex phenomenon of the virus regionally.