Since its first report in 1994, white spot syndrome virus (WSSV) has become widespread in India. We have developed a simple, rapid and sensitive monoclonal antibody (MAb)-based immunodot test for detection of WSSV. Four MAbs of IgG isotype were produced against an Indian isolate of WSSV: 1 MAb recognised a 28 kDa viral protein while the other 3 recognised both 28 and 18 kDa proteins. The 4 MAbs recognised 4 different Indian WSSV isolates collected at different times from the east and west coasts of India, indicating antigenic uniformity of the isolates. The limit of detection of the immunodot test was 500 pg of the viral protein, which compared well with 1 step PCR and could be used to detect WSSV in shrimp Penaeus monodon with and without gross signs of white spots in the cuticle. Furthermore, the test was rapid (3 h for completion) and is suitable for further development as a simple field kit. KEY WORDS: WSSV · Monoclonal antibodies · Immunodot · India Resale or republication not permitted without written consent of the publisherDis Aquat Org 51: [67][68][69][70][71][72][73][74][75] 2002 studies (Lo et al. 1998 have indicated that results positive by the highly sensitive 2-step PCR (nested PCR) are not always associated with pond outbreaks and may have a limited value for field prognosis. However, stocking of seed positive by 1-step PCR is strongly associated with outbreaks (Withyachumnarnkul 1999). Therefore, the highest priority should be to exclude broodstock and seed with high levels of infection. This would require application of less-sensitive PCR (1-step) or an alternative screening procedure of similar sensitivity. In this context, we attempted to develop a simple and sensitive monoclonal antibody (MAb)-based assay that would be suitable for fieldlevel screening of shrimp for WSSV.MAb-based tests such as immunofluorescence (Zhan et al. 1999, Shih et al. 2001), immunoperoxidase and whole-mount tissue assays (Poulos et al. 2001) have been developed for detection of the Chinese isolate of WSSV. However, such tests are not ideally suited for field level screening by farmers. Furthermore, there is evidence that the various WSSV geographic isolates differ at the molecular level ) and in virulence ). There are possibly also several variants in any country/region due to long-term intensive shrimp culture and traffic in seed. Thus, we have produced monoclonal antibodies to the Indian isolate of WSSV for antigen characterisation and for development of a simple and sensitive farmer-level immunodot test. The performance of the test was compared with PCR for screening shrimp from WSS outbreaks. MATERIALS AND METHODSVirus collection and purification. Tiger shrimp Penaeus monodon, with gross signs of white spots in the cuticle, were collected from a WSS-outbreak farm in Kundapur on the west coast of India. WSSV infection was confirmed by histopathology and polymerase chain reaction (PCR) . The foregut, gill, and epithelial tissue from the cepahalothorax were separated from the shrimp and homogenised in T...

A monoclonal antibody-based immunodot test was compared to a polymerase chain reaction (PCR) assay for managing white spot syndrome virus (WSSV) on shrimp farms at Kundapur and Kumta situated in Udupi and Uttar Kannada Districts, respectively, of Karnataka on the west coast of India. Of 12 grow-out farms in Kundapur, 6 (F1 to F6) yielded shrimp samples that were negative for WSSV by both immunodot test and 1-step PCR from stocking to successful harvest. Samples from the other 6 farms (F7 to F12) were positive for WSSV by both immunodot test and 1-step PCR at various times post stocking, and their crops failed. In the 2 farms at Kumta (F13, F14), immunodot and 1-step PCR results were both negative, and harvests were successful. In contrast to 1-step PCR results, farms F5, F6, F13, and F14 gave positive results for WSSV by 2-step PCR, and they were successfully harvested at 105 d post stocking. Our results indicate that an inexpensive immunodot assay can be used to replace the more expensive 1-step PCR assay for disease monitoring.

No abstract

Antibiotics do not show effect on infections of solely viral origin. Lumpy Skin Disease is a viral disease where antibiotics are not clinically indicated. Due to monetary worth of high producing animals, Veterinarians are resorting to use antibiotics in LSD as a preventive measure against secondary bacterial infections. Eighteen animals with lumps on the skin were selected and randomly distributed into 3 groups of 6 animals each. Two groups were treated with commonly used broad-spectrum antibiotics and the third group was treated with Neem oil topically over the lesions and were offered fresh Neem leaves smoke. As a result, Lumpy skin disease was treated economically without the inclusion of antibiotics where Neem oil and fresh neem leaves smoke guarded the animals from the risk of secondary bacterial infection. This approach eliminates the risk of antimicrobial resistance, minimises the cost of treatment, and eliminates antibiotic induced undesirable depopulation of rumen microflora.

No abstract