Effect of chemical and physical treatments on the inactivation of Macrobrachium rosenbergii nodavirus and extra small virus

White tail disease (WTD) is found to cause immense economic losses in hatcheries, with mortalities often reaching 100% within 4 or 5 days. The pathogenic agents have been identified as Macrobrachium rosenbergii nodavirus (MrNV) associated with extra small virus (XSV), which are 27 and 15 nm in diameter respectively. The effects of some chemical disinfectants hydrogen ions (pH), heat and ultraviolet (UV) irradiation on the inactivation of MrNV and XSV were investigated. The viral inoculum exposed to UV irradiation for a period of 5 min and more was totally inactivated and failed to cause mortality in postlarvae of prawn. The viruses were totally inactivated by this high pH (8.5, 9 and 10). The viral suspension treated with sodium hypochloride, formalin, Benzalkonium chloride and Benzethonium chloride at the concentration of 200 ppm caused 100% mortality in postlarvae of prawn. Iodine was found to be effective to inactivate MrNV and XSV at the concentration of 100 ppm or more, whereas the viral suspension treated with iodine at the concentration of 50 ppm or less caused mortality in postlarvae. The infected postlarvae in treated and positive control groups showed positive by RT‐PCR for these viruses.     

Molecular characterization of Streptococcus agalactiae and Streptococcus uberis isolates from bovine milk

Streptococci are one among the major mastitis pathogens which have a considerable impact on cow health, milk quality, and productivity. The aim of the present study was to investigate the occurrence and virulence characteristics of streptococci from bovine milk and to assess the molecular epidemiology and population structure of the Indian isolates using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Out of a total of 209 bovine composite milk samples screened from four herds (A–D), 30 Streptococcus spp. were isolated from 29 milk samples. Among the 30 isolates, species-specific PCR and partial 16S rRNA gene sequence analysis identified 17 Streptococcus agalactiae arising from herd A and 13 Streptococcus uberis comprising of 5, 7, and 1 isolates from herds B, C, and D respectively. PCR based screening for virulence genes revealed the presence of the cfb and the pavA genes in 17 and 1 S. agalactiae isolates, respectively. Similarly, in S. uberis isolates, cfu gene was present in six isolates from herd C, the pau A/skc gene in all the isolates from herds B, C, and D, whereas the sua gene was present in four isolates from herd B and the only isolate from herd D. On MLST analysis, all the S. agalactiae isolates were found to be of a novel sequence type (ST), ST-483, reported for the first time and is a single locus variant of the predicted subgroup founder ST-310, while the S. uberis isolates were found to be of three novel sequence types, namely ST-439, ST-474, and ST-475, all reported for the first time. ST-474 was a double locus variant of three different STs of global clonal complex ST-143 considered to be associated with clinical and subclinical mastitis, but ST-439 and ST-475 were singletons. Unique sequence types identified for both S. agalactiae and S. uberis were found to be herd specific. On PFGE analysis, identical or closely related restriction patterns for S. agalactiae ST-483 and S. uberis ST-439 in herds A and B respectively, but an unrelated restriction pattern for S. uberis ST-474 and ST-475 isolates from herds D and C respectively, were obtained. This signifies that the isolates of particular ST may exhibit related PFGE patterns suggesting detection of a faster molecular clock by PFGE than MLST. Since all the isolates of both the species belonged to novel sequence types, their epidemiological significance in global context could not be ascertained, however, evidence suggests that they have uniquely evolved in Indian conditions. Further research would be useful for understanding the role of these pathogens in bovine sub-clinical mastitis and implementing effective control strategies in India.     

Regeneration of mixed conifer forests under group tree selection harvest management in western Bhutan Himalayas

Group selection tree harvest has been proposed as an ecologically sustainable silvicultural technique in mixed conifer forests of the western Bhutan Himalayas. To evaluate this silvicultural technique, we studied the ecological consequences of a group selection tree harvest in mixed conifer forests by assessing 127 circular plots (71 in logged and 56 in unlogged stands) in two forest management units (FMUs). Tree species composition and diversity were similar between logged and unlogged stands. Seedling density and height growth vary by species and were influenced by logging and microsites, with generally taller seedlings found in the logged versus unlogged stands. Early successional shade-intolerant species colonized logged stands. Seedlings growing on bare soil scarified by harvesting had medium vigour while seedlings growing on bryophyte mats showed good vigour in both logged and unlogged stands. Moist sites with a northerly aspect supported profuse conifer seedling regeneration, compared to sites with a dry southerly aspect. Damage to conifer seedlings from herbivore browsing was minimal. Conifer seedling density and height growth was negatively affected by competition from herbaceous vegetation, most notably Salvia officinalis. Group selection tree harvest in southern dry exposures in spruce-dominated stands is silviculturally unsuitable because it alters tree succession.     

Formation of Biogenic Amines in Delayed Salt-Cured Whole and Gutted Indian Oil Sardines (Sardinella longiceps)

The formation of biogenic amines in Indian oil sardines (Sardinella longiceps) collected from the Tuticorin coast of South India and treated with delayed salt-curing was investigated. Sardines were wet salt-cured in whole and gutted forms and examined in fresh and after 6, 9, 12, and 15 h delayed conditions at ambient temperature (32 ± 2°C) at four stages of salt-curing process for quality parameters and formation of biogenic amines. Moisture content decreased from 76% to 11.3% in salting followed by drying. Similarly, water activity reduced from 0.96 to 0.74 in salt-cured sardines. In contrast, total volatile base nitrogen content increased from 79 to 3,590 mg kg^–1 in salt-cured sardines. Halophilic count of sardines was higher (8 log cfu g^–1) after salting and decreased in drying stages. The 15 h delayed salt-cured whole sardines had higher histamine contents (1,568.27 mg kg^–1), cadaverine (4,059.84 mg kg^–1), putrescine (1,604.95 mg kg^–1), and tyramine (862.94 mg kg^–1) on the final day of drying. Whole sardines had higher biogenic amines and halophilic bacterial counts than the gutted sardines. The whole and gutted sardines salt-cured up to a delay of 6 and 12 h, respectively, at ambient temperature yielded the acceptable quality products with respect to biogenic amines.     

Seroprevalence of Toxoplasma gondii infection in domestic sheep and goats in Borno state,Nigeria

Serum samples were collected from 372 sheep and same number of goats from the three geopolitical zones of Borno state, Nigeria. The samples were tested for the presences of Toxoplasma gondii antibodies by enzyme-linked immunosorbent assay. Of these, 6.7% (25/372) and 4.6% (17/372) of sheep and goats, respectively, were found to be seropositive to T. gondii antibodies, both far less than the estimated global average of 31%. Results were statistically analyzed by chi-square (χ²) test. The results showed that age, environmental conditions, and farm location are the main determinants of prevalence of antibodies against T. gondii in the study area. Older animals (>3 years) are significantly more infected than younger animals (between 6 months and 1 year).The prevalence of anti T. gondii antibodies is significantly higher (P < 0.05) in both sheep and goats sampled from the southern zone than the northern zone. Animals from the southern zones are about four times more likely to be exposed to T. gondii infection than those in the northern zone, (sheep; odds ratio (OR) = 4.25, 95% confidence interval (CI) = 1.177–15.36, P = 0.018), (goats; OR = 4.38, 95% CI = 0.925–20.73, P = 0.04). Farm location in urban area was identified as a risk factor for sheep (OR = 6.06, 95% CI = 2.53–14.54, P = 0.000), and goats (OR = 4.99, 95% CI = 1.59–15.62, P = 0.004). Current data on prevalence of ovine and caprine T. gondii in Borno state are provided by the study as well as identifying the main risk factors associated with T. gondii infection in the area.     

Estimation of Quantitative Enzymuria in Dogs With Gentamicin-Induced Nephrotoxicosis Using Urine Enzyme/Creatinine Ratios From Spot Urine Samples

The correlation between 24-hour urinary excretion of N -acetyl-β- d -glucosaminidase (NAG) and γ-glutamyl transferase (GGT) with urine NAG and GGT/creatinine ratios was assessed in dogs with gentamicin-induced nephrotoxicosis. Eighteen 6-month-oid male Beagles with normal renal function were randomly divided into 3 groups of 6. Each group was fed a different concentration of protein (high protein, 27.3%; medium protein, 13.7%; and low protein, 9.4%) for 21 days. After dietary conditioning, gentamicin was administered at a dose of 10 mg/kg IM tid for 8 days and each group was continued on its respective diet. Endogenous creatinine clearance and 24-hour urinary excretion of NAG and GGT were determined after dietary conditioning (day 0) and on days 2, 4, 6, and 8 of gentamicin administration. In addition, urine NAG and GGT/creatinine ratios (IU/L ± mg/dL) were determined from catheterized spot urine samples obtained between 7 and 10 am on the same days. The correlation between 24-hour urinary enzyme excretion and urine enzyme/creatinine ratio in the spot urine samples was evaluated by simple linear regression analysis. Spot sample urine enzyme/creatinine ratios were significantly correlated with 24-hour urinary enzyme excretion through day 4 for dogs on low dietary protein, through day 6 for those on medium protein, and through day 8 for those on high dietary protein. Mean ± SD baseline values for urine NAG/creatinine ratio and 24-hour urinary NAG excretion were 0.06 ± 0.04 and 0.19 ± 0.14 IU/kg/24 hr, respectively. Baseline values for urine GGT/creatinine ratio and 24-hour urinary GGT excretion were 0.39 ± 0.18 and 1.42 ± 0.82 IU/kg/24 hr, respectively.     

Anatomopathological aspects of avian aspergillosis

Aspergillosis is a fungal disease caused by fungi of the genus Aspergillus, in particular A. fumigatus and A. flavus. This paper focuses on anatomopathological aspects resulting from a chronic infection from Aspergillus spp in the chicken (Gallus domesticus), in the herring gull (Larus cachinnans micaelli) and in the red-legged partridge (Alectoris rufa rufa). Microscopically, we observed some histological lesions that are related to the two typical forms of Aspergillosis: a deep nodular form, typical of organs with a non-aerated parenchyma, and a non-encapsulated superficial diffuse form typical of the serosae and the lung. The observed forms of aspergillosis have been found in animals raised in poor hygienic environmental conditions or malnourished animals (chicken); in wild birds from wildlife recovery centres (herring gull), which underwent some forms of stress, such as traumas, detention, starvation, extended antibiotic treatments; in game birds (red-legged partridge) used for restocking natural areas that had been negatively affected by such stressors as captivity in aviaries, containment and transport in cages, release in unsuitable environments and malnutrition. The observed anatomopathological and istopathological aspects can therefore be regarded as the outcome of a number of factors that have reduced the typical resistance of the species and impaired the efficiency of their immune systems.     

Assessment of potentially reactive pools of aluminum in Andisols using a five-step sequential extraction procedure

A five-step sequential extraction procedure was developed for the partitioning of soil aluminum (Al) into five fractions: exchangeable, weakly organic bound, strongly organic bound, inorganic non-crystalline and crystalline. The results obtained by the sequential extraction method for Al were compared with those estimated from single extractions using identical operating conditions applied in each individual sequential fraction. The Al content in the extracts was measured by inductively coupled plasma optical emission spectrometry. The results indicated that the first four steps [potassium chloride (KCl), copper chloride (CuCl₂), sodium pyrophosphate (Na₄P₂O₇), acid ammonium oxalate ((NH₄)₂C₂O₄)] in the sequential procedure could be as effective as single extraction methods at estimating exchangeable Al, weakly organic bound Al, strongly organic bound Al, and non-crystalline Al. However, the crystalline Al content by sequential procedure was not in agreement with single extraction procedures. Further, the sequential extractions resulted in more consistent estimates of the aluminum/silicon (Al/Si) molar ratio and allophane and crystalline Al contents than single extractions method. Results of X-ray diffraction on the soil samples confirm the presence of appreciable amounts of at least three types of crystalline minerals, including gibbsite, vermiculite or halloysite. Our result implies that the sequential method can be more reliable in estimating the various Al forms in Andisols.