4. DISCUSSION
This study was conducted to describe the first official outbreak of
Lumpy skin disease (LSD) in the Gandaki Province of Nepal and to
evaluate the clinical and epidemiological features of LSD in the study
area. Two districts from Gandaki Province, Kaski, and Tanahun, were
affected with the LSD where 16 animals (12 cattle and 4 buffalo) from 9
farms were confirmed positive for LSD. This is also the first
laboratory-confirmed LSD outbreak in water buffalo from Nepal.
Before the outbreak of LSD in Gandaki province in early August 2020,
this disease was also confirmed from three other provinces of Nepal,
Province 1, Province 2, and Bagmati Province in late July 2020 (OIE,
2019d). The disease was confirmed in the Chitwan district of Bagmati
province on July 27, 2020 (OIE, 2019d) which is adjoining to the Gandaki
province. In around one week of its confirmation in Chitwan district,
cattle and buffalo in Kaski and Tanahun district started developing
clinical signs with fever, nodular lesions in the skin, swollen lymph
nodes, nasal and lachrymal discharges, and reduced milk production which
ultimately was laboratory confirmed as LSD. There was a history of
animal import from Chitwan district, where LSD was officially confirmed,
and Sarlahi where LSD has not been confirmed but its nearby districts
had confirmed LSD cases in late July. As the cattle were imported a few
months before the disease was confirmed in Chitwan, it was difficult to
conclude that LSD came to Gandaki province from Chitwan. However, this
possibility cannot be ignored as often diseases might go unnoticed for
months and might silently circulate before they finally get noticed.
In this outbreak, the clinical features exhibited by the sick animals
were swollen lymph nodes, nodular lesions in different body parts, nasal
and lachrymal discharges, and fever. These clinical features are in
confirmation with findings from other LSD outbreaks in various parts of
the world (Sameea et al., 2017; Tuppurainen et al., 2018; Ochwo et al.,
2019; Manic et al., 2019; Sudhakar et al., 2020). The morbidity rate of
4.85% with zero mortality in the current outbreak in Gandaki province
was similar to that observed during the first LSD outbreak in Odisha
state of India where 7.1% morbidity with zero mortality was observed
(Sudhakar et al., 2020).
Veterinarians and technicians have been providing supportive treatment
therapy to the affected animals using antibiotics, antipyretics,
antihistamines, and ivermectin to control ectoparasites. The Government
of Nepal has activated the quarantine system to control the animal
movement from affected areas to clean areas. However, it needs to be
more effectively implemented as the disease transmission has been
continuing despite the official animal movement restriction. It was
surprising to observe the spread of LSD over several districts despite
these animal movement restrictions and the lockdown imposed to control
the COVID-19 transmission causing limited long-distance transportation.
The possibility of illegal animal movement cannot be ignored.
Experiences from prior LSD affected countries have shown that a
combination of vaccination, animal movement regulation, and vector
control is the best control strategy for LSD (Beard, 2016; Gupta et al.,
2020). A homologous vaccine containing LSD virus or a heterologous
vaccine containing either sheep pox or goat pox virus can be used to
control the LSD (Kitching, 2003; Sprygin et al., 2020). Since the
disease is relatively new in Nepal and was only confirmed in late July
2020, vaccines are yet to be available in Nepal.
In conclusion, LSD has been confirmed for the first time in Gandaki
Province of Nepal in both cattle and water buffalo in the first week of
August after its first confirmation in Nepal in July 2020 in the eastern
part. The current morbidity and mortality are relatively low but milk
production among affected animals was nearly 60% highlighting the
possibility of huge economic losses it can cause to the dairy farmers of
Nepal. To mitigate its potential negative impact before it becomes
widespread in Nepal, we suggest the Government of Nepal decide on the
appropriate vaccine for Nepal and develop a robust vaccination strategy
and conduct risk-based ring vaccination surrounding the outbreak area.
Besides, the animal movement needs to be regulated along with raising
awareness among dairy farmers to practice biosecurity in their farms and
apply vector control measures.
5. ACKNOWLEDMENTS
We acknowledge all the dairy farmers, Veterinary Hospital Kaski and
Tanahun for their help to conduct this outbreak investigation.
6. CONFLICT OF INTERESTS
The authors declare that they do not have any conflict of interests.
7. FUNDING
There was no funding available for this study.
8. AUTHOR’s CONTRIBUTION
GKC and SK conceived the idea. GKC, BR and DKU collected the samples and
field information. PK conducted the laboratory testing. SK analyzed the
data and wrote the first draft of the manuscript. GKC created the map.
KRP provided the overall supervision and guidance. SK and GKC revised
the manuscript. All authors read and endorsed the final version.
9. ETHICAL STATEMENT
This study does not disclose farmer’s individual identifier. Consent
were obtained from the farmers to use their data for analysis. Samples
were collected by trained veterinarian registered in Nepal Veterinary
Council causing minimum pain and discomfort to the animals. No
interventions or trial were made on the animals.
10. DATA AVAILABILITY STATEMENT
All data are included within the manuscript.