Role of offending out-door aero-allergen and CD14 C(-159)T polymorphism in development and severity of asthma in a Kolkata patient population

Objective: Present study involved identification of offending out-door aero-allergens and associated genetic pathway in nasso-bronchial asthma among Kolkata population.Methods: Skin-prick test was done among 950 asthmatic patients against 11 common aero-allergens and total serum IgE concentration was measured. PCR-RFLP was done in patients and non-asthmatic control (n=220 in each) to characterize functional polymorphism, C(-159)T, of CD14, a positional candidate gene for allergy. Association of genetic polymorphisms was made with clinico-pathological conditions.Results: We identified Cocos nucifera as the most common aero-allergen sensitizer among atopic patients in Kolkata. Patients with childhood-onset asthma were significantly more sensitive towards aero-allergens and had significantly higher serum IgE level than those of adult-onset (p< 0.0001). No significant difference was found in distribution of SNP genotypes of CD14 among case and control (p=0.178). However among patients, frequency of C allele is significantly higher in childhood-onset group thanthat of adult-onset and concordantly in former CC genotype was associated with significant higher level of serum IgE than CT and TT.Conclusion: In Kolkata, pollen is a common out-door aero-allergen and Cocos nucifera is predominant among pollens. Childhood- onset and adult-onset of asthma showed significant difference in allergen sensitivity as well as genetic background with respect to CD14 polymorphism.Keywords: Asthma, aero-allergen, skin prick test, total IgE, CD14 gene polymorphis

Acaricidal activity of nishinda (Vitex negundo) leaf and garlic (Allium sativum) bulb extract against red spider mite, Oligonychus coffeae (Acari: Tetranychidae) in tea plantations of Darjeeling hill, West Bengal, India

The red spider mite, Oligonychus coffeae (Nietner) serves as a serious threat to the Darjeeling tea plantations affecting the quality of the leaves. Various plant extracts are currently being researched as an alternative to the chemical pesticides to control the red spider mites. In the present study, the leaves of Vitex negundo L. and the bulb of Allium sativum L. were analyzed for their acaricidal activity on the larval, nymphal and adult stages of the mite. Both the extracts were found to have potent activity against red spider mites and may prove to be potential acaricides in future

Typing of human rotaviruses: Nucleotide mismatches between the VP7 gene and primer are associated with genotyping failure

BACKGROUND: Rotavirus genotyping is performed by using reverse transcription PCR with type-specific-primers. Because the high rotavirus mutation rate generates an extensive genomic variation, different G-type-specific primer sets are applied in different geographical locations. In Bangladesh, a significant proportion (36.9%) of the rotavirus strains isolated in 2002 could not be G-typed using the routinely used primer set. To investigate the reason why the strains were untypeable, nucleotide sequencing of the VP7 genes was performed. RESULTS: Four nucleotide substitutions at the G1 primer-binding site of the VP7 gene of Bangladeshi G1 rotaviruses rendered a major proportion of circulating strains untypeable using the routine primer set. Using an alternative primer set, we could identify G1 rotaviruses as the most prevalent genotype (44.8%), followed by G9 (21.7%), G2 (15.0%) and G4 (13.8%). CONCLUSION: Because of the natural variation in the rotaviral gene sequences, close monitoring of rotavirus genotyping methods is important

Cluster of Nipah Virus Infection, Kushtia District, Bangladesh, 2007

OBJECTIVE: In March 2007, we investigated a cluster of Nipah encephalitis to identify risk factors for Nipah infection in Bangladesh. METHODS: We defined confirmed Nipah cases by the presence of IgM and IgG antibodies against Nipah virus in serum. Case-patients, who resided in the same village during the outbreak period but died before serum could be collected, were classified as probable cases. RESULTS: We identified three confirmed and five probable Nipah cases. There was a single index case. Five of the secondary cases came in close physical contact to the index case when she was ill. Case-patients were more likely to have physical contact with the index case (71% cases versus 0% controls, p = <0.001). The index case, on her third day of illness, and all the subsequent cases attended the same religious gathering. For three probable cases including the index case, we could not identify any known risk factors for Nipah infection such as physical contact with Nipah case-patients, consumption of raw date palm juice, or contact with sick animals or fruit bats. CONCLUSION: Though person-to-person transmission remains an important mode of transmission for Nipah infection, we could not confirm the source of infection for three of the probable Nipah case-patients. Continued surveillance and outbreak investigations will help better understand the transmission of Nipah virus and develop preventive strategies

Nipah virus outbreak with person-to-person transmission in a district of Bangladesh, 2007

In February 2007 an outbreak of Nipah virus (NiV) encephalitis in Thakurgaon District of northwest Bangladesh affected seven people, three of whom died. All subsequent cases developed illness 7-14 days after close physical contact with the index case while he was ill. Cases were more likely than controls to have been in the same room (100% vs. 9.5%, OR undefined, P<0.001) and to have touched him (83% vs. 0%, OR undefined, P<0.001). Although the source of infection for the index case was not identified, 50% of Pteropus bats sampled from near the outbreak area 1 month after the outbreak had antibodies to NiV confirming the presence of the virus in the area. The outbreak was spread by person-to-person transmission. Risk of NiV infection in family caregivers highlights the need for infection control practices to limit transmission of potentially infectious body secretions

Aetiology of Diarrhoea in a Birth Cohort of Children Aged 0-2 Year(s) in Rural Mirzapur, Bangladesh

The incidence of aetiology-specific diarrhoea and the pathogenicity of infectious agents in a birth cohort (n=252) in rural Bangladesh were determined. Stool specimens or rectal swabs were collected from diarrhoeal cases over two years and routinely on a monthly basis. Stool samples from children with diarrhoea were compared with stool samples from children without diarrhoea to calculate rates of isolation and pathogenicity of agents. In total, 1,750 stool specimens from diarrhoea patients and 5,679 stool specimens from children without diarrhoea were tested. An infectious agent was identified in 58% of the stool specimens from diarrhoea patients and 21.6% of the stool specimens from children without diarrhoea. The most commonly-isolated pathogens from all specimens were enterotoxigenic Escherichia coli (ETEC), enteroadherent E. coli, Shigella , Campylobacter jejuni , Giardia , and rotavirus. ETEC (ST and LT-ST toxin), enterotoxigenic Bacteroides fragilis , Shigella, and rotavirus were associated more with disease than with asymptomatic infections. Aetiology-specific infections were associated with acute episodes. The isolated enteropathogens were essentially the same as those found in other tropical rural settings. Enterotoxigenic B. fragilis was also identified as a pathogen. Ongoing vaccine efforts focusing on Shigella, rotavirus, and ETEC would be useful

Prevalence of G2P[4] and G12P[6] Rotavirus, Bangladesh

Rotavirus strains not covered by licensed vaccines are increasing

Incrimination of Blomia tropicalis as a Potent Allergen in House Dust and its Role in Allergic Asthma in Kolkata Metropolis, India

Background Theincreasing trend in allergic diseases has become obvious in the present day, especially in developing countries like India, because of many factors such as change in ambient air quality, increased air pollution, metamorphic change in living habits and lifestyle, and climate 1. Mites present in house dust represent a major source of allergens, resulting in different allergic manifestations all over the world, and hypersensitivity to these dust mites may play a pivotal role in pathogenesis of several allergic complaints including bronchial asthma. The present study evaluated the sensitization toward house dust and house dust mites among patients residing in Kolkata metropolis, India, who are suffering from allergic asthma.Methods The skin prick test was performed on a total of 1079 patients (585 males and 494 females) between the age group 5-50 years and 50 healthy controls using a variety of 16 common aero-allergenic extracts including 4 allergens of interest, viz. Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis and total house dust allergens. Total serum IgE level was measured by using the EIA technique and specific IgE levels against aforesaid allergens were detected with the Pharmacia ImmunoCAP 100 System. The influence of age and sex, if any, on allergen sensitivity was also investigated. All statistical analyses were performed using SPSS 10.0 for Windows and Zar 2.Results The responses among patients with asthma to house dust and house dust mite allergen tests were as follows: house dust (96.22%), D. pteronyssinus (75.06%), B. tropicalis (72%), and D. farinae (63.72%). The frequency of positive skin response was found to be independent of age and sex. The total serum IgE levels in patients varied between 7.3 and 4040 IU/ml (mean 369 ± 26.51 IU/ml). Specific IgE antibody test proved that 83% patients showed sensitivity toward at least 1 of the allergens tested.Discussion The results indicate that patients are highly sensitive to house dust and 3 other allergenic mites, namely, D. pteronyssinus, D. farinae, and B. tropicalis, as evidenced by the skin prick test, quantification of total serum IgE, and detection of allergen-specific IgE antibodies among patients of Kolkata. Although mites belonging to the genus Dermatophagoides have already been incriminated as a major source of allergen in house dust in India, this is the first time the role of B. tropicalis mites causing allergic asthma has been reported from an Indian population. Thus, the importance of B. tropicalis mite as an aetiopathological agent in causing various allergic manifestations among the Kolkata population should not be undermined and the allergen should be included in routine allergy testing. Keywords: allergy, Dermatophagoides spp, Blomia tropicalis, house dust, skin prick test, Ig