Sero-Prevalence of West Nile Virus in Urban and Peri-Urban Poultry Farms of Guwahati, India

West Nile virus (WNV) is a zoonotic, emerging mosquito-borne virus which can cause severe disease in the form of encephalitis and acute flaccid paralysis in humans. In Assam, northeast India, arboviruses seem to be re-emerging, however, WNV has been little studied. The present investigation was carried out from April, 2018 to March, 2019 to study sero-positivity of WNV in chicken in urban and peri-urban areas of Guwahati, the capital city of Assam. Four urban and four peri-urban areas of Guwahati were selected. A total of 864 chicken serum samples (72 samples per month) were screened by ELISA and further confirmed by haemagglutination inhibition (HI), which revealed that 3.13% of the chickens had been exposed to WNV, with 0.69% sero-positivity in urban areas compared to 5.56% in peri-urban. Peak sero-prevalence of WNV were reported during the month of July and August with 8.33% each with lowest sero-prevalence being recorded in November (1.39%) and no sero-positive birds from December to April. These results indicate that WNV is one of the actively circulating flaviviruses in Assam, and human febrile and encephalitic cases should be screened for the disease.

Pesticide Residues in Peri-Urban Bovine Milk from India and Risk Assessment: A Multicenter Study

Pesticides residue poses serious concerns to human health. The present study was carried out to determine the pesticide residues of peri-urban bovine milk (n = 1183) from five different sites (Bangalore, Bhubaneswar, Guwahati, Ludhiana and Udaipur) in India and dietary exposure risk assessment to adults and children. Pesticide residues were estimated using gas chromatography with flame thermionic and electron capture detectors followed by confirmation on gas chromatography-mass spectrometer. The results noticed the contamination of milk with hexachlorocyclohexane (HCH), dichloro-diphenyl trichloroethane (DDT), endosulfan, cypermethrin, cyhalothrin, permethrin, chlorpyrifos, ethion and profenophos pesticides. The residue levels in some of the milk samples were observed to be higher than the respective maximum residue limits (MRLs) for pesticide. Milk samples contamination was found highest in Bhubaneswar (11.2%) followed by Bangalore (9.3%), Ludhiana (6.9%), Udaipur (6.4%) and Guwahati (6.3%). The dietary risk assessment of pesticides under two scenarios i.e. lower-bound scenario (LB) and upper-bound (UB) revealed that daily intake of pesticides was substantially below the prescribed acceptable daily intake except for fipronil in children at UB. The non-cancer risk by estimation of hazard index (HI) was found to be below the target value of one in adults at all five sites in India. However, for children at the UB level, the HI for lindane, DDT and ethion exceeded the value of one in Ludhiana and Udaipur. Cancer risk for adults was found to be in the recommended range of United States environment protection agency (USEPA), while it exceeded the USEPA values for children.

Brucellosis in India: results of a collaborative workshop to define One Health priorities

Brucellosis is an important zoonosis worldwide. In livestock, it frequently causes chronic disease with reproductive failures that contribute to production losses, and in humans, it causes an often-chronic febrile illness that is frequently underdiagnosed in many low- and middle-income countries, including India. India has one of the largest ruminant populations in the world, and brucellosis is endemic in the country in both humans and animals. In November 2017, the International Livestock Research Institute invited experts from government, national research institutes, universities, and different international organizations to a one-day meeting to set priorities towards a "One Health" control strategy for brucellosis in India. Using a risk prioritization exercise followed by discussions, the meeting agreed on the following priorities: collaboration (transboundary and transdisciplinary); collection of more epidemiological evidence in humans, cattle, and in small ruminants (which have been neglected in past research); Economic impact studies, including cost effectiveness of control programmes; livestock vaccination, including national facilities for securing vaccines for the cattle population; management of infected animals (with the ban on bovine slaughter, alternatives such as sanctuaries must be explored); laboratory capacities and diagnostics (quality must be assured and better rapid tests developed); and increased awareness, making farmers, health workers, and the general public more aware of risks of brucellosis and zoonoses in general. Overall, the meeting participants agreed that brucellosis control will be challenging in India, but with collaboration to address the priority areas listed here, it could be possible.

Mosquito abundance and pig seropositivity as a correlate of Japanese encephalitis in human population in Assam, India

Background & objectives

Assam is the most vulnerable state for Japanese encephalitis (JE) in India. The situation warrants characterization of epidemiological patterns of JE in vectors, pigs and human population. This investigation was aimed to determine the relative abundance of mosquito species and seroprevalence of JE in pigs in order to draw an epidemiological association with reported human JE cases in Assam.

Methods

Pig sera and mosquitoes from selected farms in Sivasagar and Kamrup districts of Assam were collected fortnightly for one year during June 2015-May 2016. Pig sera were tested for JE antibodies by haemagglutination and virus neurtralization tests. Mosquito species were identified microscopically following the taxonomic keys. The results were analyzed with data on confirmed human JE cases in the selected districts.

Results

Culex gelidus (26.07%) and Cx. tritaeniorhynchus (24.07%) were the most abundant species in collected mosquitoes (n = 997). A total of 22.99% of pigs (n = 335) were JEV seropositive and 45.65% of human acute encephalitis syndrome cases (n = 230) were positive for JE virus (JEV) infection. Relative mosquito abundance, pig positivity and human cases were highest during monsoon (June-September) and least during winter (December-February). Rise in mosquito population was observed during pre-monsoon season (March-May) and concurrently higher number of human cases and pig seropositivity were recorded. A good correlation was observed between mosquito number and JEV positivity in pigs/human, and between pigs and human cases (p < 0.05). Human population in Sivasagar was at higher risk for JE infection (OR: 6.46, p < 0.0001) than in Kamrup rural district.

Interpretation & conclusion

This study indicates that a seasonal correlation exists between mosquito abundance and JEV seroconversion in pigs with concurrent human JEV outbreaks under field conditions in Sivasagar and Kamrup rural districts of Assam and that monitoring mosquito abundance/density and pig JEV seropositivity may help in predicting JEV outbreak in human population in the region.

Virulence gene profiling of porcine Pasteurella multocida isolates of Assam

Aim:

The present study was conducted to detect and identify the virulence genes in Pasteurella multocida isolates of porcine origin from Assam.

Materials and Methods:

A total of 21 porcine P. multocida isolates were subjected to capsular typing and detection of virulence-associated genes (pfhA, tbpA, hgbB, toxA, oma87, ompH, and nanB) using various polymerase chain reaction (PCR) methods reported elsewhere. Further, pathogenicity of the porcine isolates of P. multocida was studied in mice. For each strain of P. multocida selected for pathogenicity trial, the group of mice was injected intraperitoneally (i/p) with 0.1 ml of the inoculum prepared from respective field isolates, containing 10⁹ organisms per ml.

Results:

Capsular typing of the isolates by multiplex PCR showed two capsular types, type A (66.66%) and type D (33.33%). All the isolates were positive for outer membrane protein genes, oma87 and ompH genes. Iron acquisition genes, tbpA and hgbB, were detected in 14.28% and 19.04% of the isolates. The dermonecrotoxin encoding gene, toxA, was present in 23.80% of the isolates. Filamentous hemagglutinin encoding gene, pfhA, was detected in 28.57%. The virulence gene distribution pattern of the isolates indicates the important role of the genes in disease pathogenesis.

Conclusion:

From the present study, it can be concluded that toxA gene is an important marker gene for defining the pathogenic potential of P. multocida strains in swine.

Effect of starter cultures and packaging methods on amino acid profile and eating quality characteristics of pork ham

Wet cured pork hams were inoculated with a mixed starter cultures comprising of Lactobacillus acidophilus and Micrococcus varians M483 at the dose level of 106 cfu/g and the un inoculated hams served as controls. The amino acid profile of hams of the treated and the control groups stored at 4oC under MAP and VP and evaluated on 60th day of storage revealed that treated hams liberated higher concentration of free amino acids except for proline and methionine which were found in higher concentration (P < 0.01) in the MAP control samples. The MAP control samples liberated glutamic acid (85.65 ± 1.40 ppm), cystine (21.56 ± 1.14 ppm) and tyrosine (16.63 ± 1.94 ppm) whereas, the treated samples did not release these amino acids. The VP control samples too liberated cystine (6.98 ± 1.36 ppm) and arginine (42.70 ± 2.78 ppm) but the treated ham of the VP did not liberate these amino acids. The VP hams had higher concentration (P < 0.01) of free proline, glycine, alanine, valine, methionine, isoleucine, phenylalanine, lysine and histidine than the MAP samples. Colour analysis of ham using CIE Lab colour system revealed that the treated samples had significantly higher concentrations of L*, a* and b* components. The L* and a* values were higher in the MAP than under VP systems while the b* values were higher in the VP samples than the MAP samples. Neither the bacterial cultures nor the packaging system influenced the textural property of ham. Starter cultures inoculated hams were rated superior (P < 0.05) in terms of their sensory properties. Hams packaged under MAP were rated superior (P < 0.05) than those packaged under VP in terms of appearance, colour, taste, tenderness, flavour, juiciness and overall acceptability.

Effect of incorporation of fermented bamboo shoot on physicochemical and microbial quality of pork pickle

Replacement of commercial chemical preservative (Vinegar) by incorporating fermented bamboo shoot (FBS) products partially or completely and their effect on physicochemical, microbial and shelf life qualities on pork pickle products was studied. Different FBS products such as FBS extract, paste and powder were incorporated in the pork pickle products at the level of 50 to 100 % with or without vinegar and stored at room temperature for 90 days. Highest pH values and lowest titrable acidity was recorded in products with 50 and 100 % FBS powder. No significant differences were observed with respect to proximate composition i.e. percent moisture, protein, fat and ash contents among the products except the product with 100 % FBS powder which had significantly (p < 0.01) lower moisture content. Microbial load (Log total plate counts) and thiobarbituric acid (TBA) values were found to be increasing as the storage periods were advancing. Except the product with 100 % FBS powder which could be stored for 30 days only, other products could be stored upto 90 days without any physicochemical and microbial problems. It can be concluded from this study that natural and organic FBS extract and paste can be used successfully replacing the conventional chemical preservative (Vinegar) for preparation of pork pickle products and preserved more than 90 days at room temperature. However, FBS powder can be used for preservation of the pickle products for a short period (30 days).

Verotoxic Escherichia coli (STEC) from beef and its products

In the present investigation, out of 27 (24.10%) strains of Escherichia coli isolated from 112 beef samples comprising raw meat (45), kabab (36) and kofta (31), 9 (33.33%) belonging to 7 different serotypes were verotoxic as tested by vero cell cytotoxic assay. Serotype O145 was the predominant STEC in raw meat. Interestingly, one STEC-O157 strain was also detected. All the STEC strains were positive for Stx genes by polymerase chain reaction showing stx2 (77.78%) to be most predominant followed by stx1 (22.22%). Phenotypic enterohaemolysin production on washed sheep blood agar supplemented with CaCl2 revealed 6 (66.67%) STEC strains to be positive. Presence of STEC in cooked beef products, viz., kabab and kofta appeared to be a matter of concern and potential threat to public health.

Cutaneous infection associated with Staphylococcus hyicus in cattle

Forty-seven Staphylococcus hyicus strains, one each from 47 of 81 cattle examined, were isolated from cutaneous lesions on different parts of the body. Nineteen of the strains were isolated in pure culture and the rest were isolated in association with either other staphylococci or microfilariae or mange mites. Three out of 10 representative strains produced cutaneous lesions when inoculated intradermally into rabbits.