Abstract:
Growth of shrimp industry in Sri Lanka has been severely affected, time after time,
by three reported viral diseases-White spot disease, Monodon Bacculoviral disease
and Yellowhead disease. However, incompatible disease symptoms to those, that
were found in shrimps during the recent past, led to discover another shrimp viral
disease in Sri Lanka - Infectious Hypodermal and Hematopoietic Necrosis Virus
(IHHNV). It has been listed by World Animal Health Organization (OIE) as a
disease causing severe economic losses, but with low mortality in Penaeus monodon.
Despite the economical significance, however, prevalence of IHHNV in Sri Lanka
has not properly been studied. Therefore, the aim of this study was to investigate the
prevalence of IHHNV in wild caught broodstock (BS), hatchery reared post larvae
(PL) and farmed Penaeus monodon. Samples were collected representing broodstock
collecting regions of the country. PCR was done using IQ 2000TM test kit for the
samples collected during the years of 2017 and 2019. In 2017, 131 samples of BS
collected from two BS collecting areas, 54 samples of PL represnting03 BS
collecting areas and 66 pond samples representing 02 shrimp farming provinces were
tested. Results revealed that 31.3% BS, 24.07% PL and 18.03% of farmed shrimp
samples were positive for the IHHNV and the severity of most of the infection was
recorded as very light. From the samples collected in 2019, 44 BS samples
representing 05 BS collecting areas, 30 PL samples from02 BS collecting areas and
18 pond samples from 01 shrimp farming province (North Western Province) were
tested and the results indicated that 27.27% BS, 16.67% PL and 5.56% of farmed
samples were slightly positive for IHHNV. Therefore, this study provides the
evidence to show the prevalence of IHHNV in Penaeus monodon in Sri Lanka, in all
three life stages that is important for farming. As IHHNV is more severe in P.
vannamei than that of P. monodon, emphasis should be made in strengthening Good
Management Practices for the success of both P. monodon & P. vannamei industries.
