Rate (ROI) and severity (SOI) of infection of white spot disease in cultured and captured Penaeid shrimps in the Persian Gulf using histopathology and polymerase chain reaction

White Spot Disease (WSD) is well known as a widespread viral disease in shrimps from 1992. Many studies focused on morphological, histopathological and epidemiological characteristic and pathogenecity of the disease but less on the determination of the severity of WSD using the histopathological features in target tissues. A generalized scheme for assigning a numerical qualitative value to severity grade of infection considering to histopathology and counting the inclusion bodies in different level of infection and different microscopic fielding immersion lens was accomplished before. This study was conducted in order to estimate the rate of infection (ROI) and the severity of infection (SOI) of WSD in native shrimps in the Persian Gulf. About 90 live specimens of affected cultured Penaeus indicus were collected from Abadan region, south Iran and 150 specimens of native shrimps were captured from the Persian Gulf. Histopathological changes were observed by light microscope in target organs such as: gills, cuticular epidermis, heart, hemolymph, fore stomach and hepatopancreas. ROI and SOI were estimated respectively by standard formulas and grading between 0-4 based on the percentage of white spot syndrome virus WSSV positive cells in selected fields of microscope. The results were confirmed by conducting nested PCR method. The SOI of Parapenaeopsis stylifera was estimated in grade four and its ROI was about 85% as the most susceptible species. Histopathologic infection of Metapenaeus affinis shrimp by WSD was observed also during this stud

Tracking of Hepatopancreatic parvo-like virus (HPV) disease in Litopenaeus vannamei of the hatcheries in the Bushehr Province

Presence of hepatopancreatic parvo-like vines (HPV) disease was assessed from June until October 2009 in Litopenaeus vannamei hatcheries and grow-out farms of the Bushehr province. Samples were collected from 6 hatcheries and 6 grow-out farms located in coasted areas. From each hatchery, 100 PL samples with average age PL5-PL8 and 20-30 samples from each grow-out farm with average age 105 to 120 days were collected. The samples were divided into three groups one used for gross sign and wet mount with Gimsa, the second group was preserved in Davidson Fixative and used for histopathology and the third group was fixed in ethyl alcohol 95% and used for polymerase chain Reaction (PCR). In gross sign 30%- 40% of the shrimp showed different sizes and some were smaller than the others. In the wet mount group with Gimsa staining of hepatopancrease, the inclusion body with basophilic color was seen. The histopathology indicated that the hepatopancreatic cell was infected and the basophilic inclusion body observed in many samples. The PCR examined with IQ 2000 Kit was negative. The rate of infection (ROI) was 1.1% for hatcheries and 32% for grow-out farms

The status of white spot syndrome virus (WSSV) in Islamic Republic of Iran

White spot syndrome virus (WSSV), the causative virus of disease, is found in most shrimp farming areas in Iran, and it causes large economic losses to the shrimp farming industry. Shrimp aquaculture is an important industry in Iran and plays an important role in aquaculture production. The shrimp production in 2012 was more than 12000 metric tonnes and it is estimated it will reach 20000 tonnes in 2013. White spot syndrome virus is highly virulent in shrimp farms and can spread quickly and cause up to 100% mortality within 3-7 days. The virus is a very large, enveloped, double stranded DNA (ds DNA) and assigned by ICTV to a new genus Whispovirus and belong to Nimaviridae family. In Iran WSSV first appeared in Khuzestan Province in the south of Iran, and later on it appeared in other provinces such as Bushehr, and Sistan and Baluchestan. The aim of this review is to give current information of WSSV in Iran, host ranges, carriers, biology, clinical signs, histopathology, PCR, with emphasis on the effects of WSSV in shrimp aquaculture

Identification of white spot syndrome disease (WSSD) in Penaeus indicus by polymerase chain reaction (PCR) method in Iran

A high mortality of cultured shrimp Penaeus indicus was spotted in summer 2002 in Khouzestan province, southwestern Iran. White spots with a size of 0.5-2mm was one of the typical external signs of the infected shrimps. Our examination revealed that the cuticle of the shrimps could be easily separated from their epidermis, their hepatopancreas was swollen, their abdomen and intestine were empty and their body colour was reddish. Based on the symptoms, we suspected that white spot syndrome disease (WSSD) might have caused the mortality. To ascertain our suspicion, we collected 90 infected specimens from the Khouzestan province and another 120 uninfected specimens from Bushehr and Hormozgan provinces in the south and Golestan province in the northeast Iran. After fixing the samples in pure alcohol, we homogenized the samples and extracted their DNA content using phenol-chloroform methods. Using a WSSD kit, we conducted the PCR method which showed the specimens from Khouzestan province (Abadan area) were definitely infected with WSSD while results for samples from other provinces were negative

Screening and evaluation of indigenous bacteria from the Persian Gulf as a probiotic and biocontrol agent against Vibrio harveyi in Litopenaeus vannamei post larvae

Isolation of autochthonous bacteria from marine sources as a potential probiont in biocontrolling against pathogenic Vibrio species in the shrimp culture industry was the aim of current research. A total of 198 bacterial strains were isolated from pond water, sediment, hepatopancreas and gut samples of shrimps after culturing the samples on Tryptic Soy Agar and incubated at 30 °C for 24-48 h. The isolates were tested for their antagonistic activity in contact with Vibrio harveyi. Two strains (IS02 and IS03) that isolated from the gut and pond sediment were showed antagonistic against V. harveyi. According to 16S ribosomal DNA gene sequence analysis, the strain IS02 was identified as Bacillus subtilis and IS03 as B. vallismortis. Further, the two bacterial species, B. subtilis and B. vallismortis were challenged separately for probiotic activity in the post larvae of Litopenaeus vannamei against pathogenic V. harveyi. The present study identified B. subtilis IS02 and B. vallismortis IS03 had biocontrol activity against V. harveyi in vitro and in vivo and they increase growth performance of L. vannamei in post larvae stage

Effects of Laminaria digitata and Aschophylum nodossum in controlling white spot disease (WSD) in white leg shrimp (Litopenaeus vannamei)

Complementary feedstuff extract from Laminaria digitata and Ascophylum nodossum containing 1% alginic acids as stimulator of immune system in Litopenaeus vannamei for controlling WSSV was used in this study. The test shrimps, Litopenaeus vannamei, in larvae stage (Z1-131,1), post larvae stage (PL1-PLO and juvenile (from day 30 to 40) were fed by complimentary feed stuff as the other test conditions in the test and control group were the same. Both groups were exposed to WSSV after 40 days by oral inoculation. The clinical signs and mortality were recorded for 10 days. The results showed the survival rate of the test group was higher than the control group and it was significant (P<0.05). The results also showed that the mortality in the test group occurred 48 hours later than the control group. This study can lead us to new methods for controlling White Spot Disease

The effect of created hemolymph apoptosis on WSSV Gamma-vaccinated shrimp, Litopenaeus vannamei in WSSV disease control

White spot syndrome virus (WSSV) is the causative agent responsible for huge-shrimp viral epidemics in shrimp farms throughout the world. Our study was aimed to determine the effect of WSSV Gamma-vaccinated Litopenaeus vannamei on the occurrence of apoptosis. One thousand and twenty PL15 were randomly distributed among 2 treatments and two control groups. Gamma-Vaccinated shrimp and non-Gamma-vaccinated ones were our treated and untreated groups. Based on our results significant differences (p<0.05) were observed in survival percent between vaccinated-exposed group (82.33±2.51) and non-vaccinated exposed group (26.00±10.00). It is concluded that apoptosis can be a helpful process in enhancing the immune response in shrimp especially against WSSV

Experimental pathogenicity of shrimp, Penaeus vannamei exposed to monodon baculovirus (MBV)

The objective of our study was to explain the histopathological changes of monodon baculovirus (MBV) in hepatopancreas and midgut tissues of the cultured Penaeus vannamei. Five-hundred and forty juvenile of P. vannamei with average size of 7.99±0.54 g and 3600 post larvae 10-15 were distributed to 18 glass aquariums (50×50×60cm) with 100L well aerated water per each aquarium as water borne MBV (group A) and food borne MBV (Group B) and one control group (C), in triplicates. Also, 3600 post larvae were dedicated for water borne exposure (D) based on one time immersion exposure in 24 h without water exchange and the untreated group was studied as control in triplicates. The specific pathological sign of MBV was observed as a multiple intranuclear eosinophilic occlusion bodies (OBs) in hepatopancreas and midgut tissues. Our result indicates that the severity of the MBV infection is more considerable in post larvae than juvenile stage and confirms that MBV can be an invasive pathogen for shrimp culture industry in Iran

A review of the health status and diseases of cultured Penaeus indicus in Sistan-o-Baluchistan Province, Iran

The health status and diseases of Penaeus indicus in Sistan-o-Baluchistan culture ponds of Guater Site were assessed during the year 2005. Over the shrimp culture period, two ponds were selected from two farms, and 19 shrimp specimens were caught randomly each month from each pond. The specimens were immediately transferred to lab for further investigation. After recording abnormal signs including color change of cuticle and gills, presence of white or black spots on the body, the specimens were studied for bacterial, fungal and parasitic infections. Bacterial infections included Citobacter, Pseudomonas, Aeromonas, Actinobacter, Proteus, Vibrio alginolyticus, V. harveyi, V. parahaemolyticus, V. spelendidus and Vibrio sp. Fungal infections of the cultured P. indicus included Fuzarium spp., Mucor, Cladosporium, Aspergillus spp., Penicllinium spp., sterilized hyphae and yeast. The parasites found included Zoothamnium, Epistylis, andVorticella. Since the second month of shrimp culture onwards around 10-65% of shrimps showed white and opaque spots on abdominal muscle which started from the sixth segment. Sometimes, the dots covered the whole abdomen, giving the shrimps a cooked look and a yellowish watery sac on hepatopancreas under the carapace of the specimens could be observed. There was no evidence of disease agents based on microbial, parasitic and environmental studies. The food which was used for shrimp culture was analyzed and showed anion and cation imbalance. Our results showed Idiopathic Muscle Necrosis Syndrome (IMNS) and Subcarapace Watery Sac Syndrome (SWSS) sings in the cultured shrimps

Study of total hemocyte count and total plasma protein in immune system of freshwater crayfish (Astacus leptodactylus)

In this study, hemocytes defense cells and total plasma protein had been studied in immune system of freshwater Crayfish Astacus leptodactylus. About one-hundred freshwater Crayfish (A.leptodactylus) with average weight of 25-40g were purchased from Aras dam reservoirs in west Azarbayjan province and transported to Iranian artemia research center of Orumya province.(25 pieces of Crayfish were considered surplus for possible losses) Before experimernt the Crayfish were acclimated for two days in the laboratory and then disinfected by oxytetracycline antibiotic and finally, an equal number (15 pieces of Crayfish in each glass aquariums) transported to 5 glass aquariums. In order to study hemocyte and plasma total protein, the hemolymph samples were withdrawn from abdominal second segments of Crayfish in interval hours (0, 6, 12, 24, 48, 96, 144, 240 and 336). Result showed that the mean of hemocytes was 27-114 CFU ml^-1, and the highest and lowest value of hemocytes were 180 and 12 CFU ml^-1 in 12 and 336 hours after experiment times, respectively. Also based on the results, the semigranular cells (SGC) and granular cells (GC) were approximately comprised about 58-65% and 28- 37%, respectively and hyaline cells (HC) about was 3-6%. Based on total plasma protein results, the mean of total plasma protein was 1-2 Gr dl-1 , and the highest and lowest value of total plasma protein were 2/8 and 0.5 Gr dl-1 in 12 and 336 hours after experiment times