Epidemiology Of Influenza Virus H5n1 In Islamabad Capital Territory
Material type: Book ; Literary form:
Publisher: 2016 Dissertation note: The poultry sector in Pakistan is the second largest industry that contributes to the national gross domestic products (GDP) and remains a major source of nutrition (protein and energy) for human population in Pakistan. Highly Pathogenic Avian Influenza (HPAI) outbreaks due to H5N1 virus in poultry have been recorded in over 62 countries, indicating the contagious nature of the disease and its potential to infect various avian species. These HPAI outbreaks in poultry have lead to killing/culling of around 120 million birds in various countries. During 2009, the Avian Influenza continues to occur in poultry in China, Hong Kong, India, Egypt, Nepal, Bangladesh and Canada . In Pakistan, an HPAI outbreak due to H7N3 virus was first observed in 1994-95 and those due to H9N2 virus in broiler and layer chickens were recorded between late 1990’s and early 2000. During the period between 2006 and 2008, poultry heavily suffered due to multiple outbreaks caused by H5N1 virus.
The country experienced several and severe HPAI subtype H5N1 outbreaks during 2006-2008 in commercial poultry farms mostly, causing mass economic losses. In Pakistan all the four poultry production system exists being identified by FAO. The present study was conducted in peri-urban areas of ICT Islamabad, capital of Pakistan. The objectives of the present study were to investigate the outbreaks due to HPAIV H5N1 in 2006-2007 in ICT and identify the pattern and trends of these outbreaks. For this purpose descriptive epidemiological study was conducted and data was collected on a predesigned questionnaire regarding farm demography, culling, morbidity and mortality. The result statistical analysis showed a significantly (P< 0.05) higher morbidity, mortality, case fatality and culling rate in layers farms than breeders and broilers respectively. Layers and breeders of old ages were mostly affected with having higher mortality and culling in comparison to younger age layer and breeder commercial farms. The mean morbidity and mortality rates ranged 57–95% and 5-43% correspondingly.
After the HPAIV H5N1 first reported outbreak in Pakistan in 2006 culling strategy was adopted after devastating outbreaks regularly reported from throughout the country. The reasons behind these emerging epidemics were unknown and several hypotheses were given birth after these outbreaks. Knowledge regarding potential risk factors responsible for HPAIV H5N1 epidemics in commercial poultry farms in Pakistan was lacking. Therefore we conducted a longitudinal cross sectional survey (1:1 matched case control study) to identify potential risk factors at farm level responsible for 2006-2007 HPAIV H5N1 infection in poultry in ICT. Information on farm characteristics, biosecurity practices and farm management were collected. Logistic regression model on data was used to unveil the potentially associated risk factors with cases (farms confirmed HPAI H5N1 Positive). Several candidate variables were studied and investigated for association. The results multivariable logistic regression showed that farm location such as in urban area (P<0.05: OR=18.50), wild birds entry (P<0.05: OR= 12.66) and farms situated in highly dense poultry populated area (P<0.05:OR=4.50) were found significantly associated with outbreaks of HPAIV H5N1 infection in commercial poultry farms during 2006-2007 epidemics in the study area.
Live bird markets (LBMs) are essential for poultry marketing in developing countries like Pakistan. One year active disease surveillance for influenza viruses in avian species in LBMs in ICT area was conducted in 2011. LBMs in Pakistan are typically urban that brings together many avian species produced by different suppliers. Which make LBMs in Pakistan a potential source of HPAIV viruses as well as other emerging poultry pathogens i.e. new castle disease virus,infectious bronchitis etc. The results of the present surveillance data showed that seroconversion against H5N1 and H9N2 is present in LBMs bird species which were isolated from different samples like serum, cloacal, nasal samples and organ samples.This indicates the continuous threat of AIV viruses circulating in the live bird markets set up of Pakistan.
Findings of these studies will help to tailor control and prevention measure against devastating outbreaks in future regarding the local circumstances of commercial poultry farms as well as in LBMs. These studies also succeeded to unveil the true reasons behind these devastating outbreaks and their higher impact on poultry industry. Such type of surveillance programs will be useful in future to investigate several emerging diseases and outbreaks in Pakistan and other developing countries.
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Molecular Epidemiology Of Mycobacterium At The Animal Human Interface And Its Co-Morbidity With Diabetes Mellitus
Material type: Book ; Literary form:
Publisher: 2016 Dissertation note: Tuberculosis (TB) is a common and fatal infectious disease which has afflicted mankind for several millennia. At the moment, TB is positioned at number five when it comes to the most common causes of fatality worldwide. TB is curable if it is properly diagnosed and treated. In 2015, it was estimated that 1.5 million deaths (an equivalent of 4,000 deaths per day) and 9 million new TB cases have been reported. Diabetes Mellitus is also widely distributed and estimated to affect 366 million people by 2030. The co-morbidity of DM and TB is re-emerging because of the progressive epidemiology of both diseases especially in the developing countries. Endemicity of TB and DM is growing in developing countries because of low socio-economic status and poor living conditions.
In this study, a total of 500 tuberculosis positive patients were selected under TB DOTS program from five tertiary care hospitals of Lahore. Sputum samples were collected from all the enrolled patients and smear microscopy was performed for TB confirmation. Blood samples were collected from the same patients for screening of diabetes mellitus. Sputum samples were also processed for culture and drug sensitivity on LJ medium. Molecular identification by PCR technique was carried out on all positive cultured strains and results were compared with reference strain H37RV. For DNA sequencing, PCR products were sent to Singapore where sequencing was performed by Sanger method.
Data was compiled and variables including gender, age, drug resistance and treatment history and correlation among different variables was analyzed using chi-square test and Fischer’s exact test method at P-value of ≤0.05. SPSS (Statistical Package for Social Sciences, Version 20.0) was used for statistical analysis. The count data was statistically analyzed using
descriptive statistical tools. On screening for fasting blood sugar level, 74 (14.8%) patients were recorded as diabetics as well i.e. blood sugar level ≥ 126 mg/dl. Out of these 74 patients, 22 patients had previous history of diabetes whereas remaining 52 patients were newly diagnosed at the time of screening. The maximum distribution of TB-DM patients was found in age group > 57 years. Mean age of the group without DM was 39 years and with DM was 48 years. Coexistence of DM in TB patients was higher in males (62.2%) as compared to female study subjects. However, the gender difference is statistically non-significant (p value 0.243).
The distribution of education level revealed that out of the total participants, maximum number of patients (n=220) were illiterate and similar trend was observed in diabetic patients with 54 (73%) individuals belonging to the illiterate group of the subjects. There is statistically significant difference between existence of DM and literacy level in tuberculosis patients. Among social and behavioral risk factors in tuberculosis patients, majority of the patients were unemployed (24%) in TB-DM group. Significant correlation p value ≤ 0.05 was found between coexistence of TB-DM and tobacco use. TB cases with diabetes were known to have history of smoking with 73% (n=54) while non-smokers were 27% (n=20).
On sputum smear microscopy frequency of 3+ results showing high bacterial load, was profoundly higher i.e. 67.6% in diabetic tuberculosis patients as compared to non-diabetics which was 4.9% only. Total culture yield was 363 out of 500 sputum samples. There were 193 samples that were sensitive to all drugs, 9.4% were MDR strains (resistant to Isoniazid and Rifampicin). MDR-TB is significantly higher in TB-DM patients i.e. 13.5% as compared to 8.7% in TB only patients.
In our study, DNA sequence data for drug resistance was studied by the sequence of rpoB gene of the wild type MTB strain. Sequencing results showed mutations at various spots of rpoB gene.
Most common mutational sites identified were at codon 531, 526 and 516 with frequency of 70%, 15% and 7.5%, respectively. Moreover, mutation sites at 512 and 574 codon had also been reported. In this study, predominantly two phylogenetic variants were identified. Majority of the isolated strains were Central Asia Strain (CAS) with a prevalence of 88.2% and rest were Beijing strain. However, attempts to find zoonosis could not be established. A total of 900 raw milk samples were also screened for M. bovis and no positive sample could be detected.
The present study emphasizes the importance of screening for DM in TB patients, which had not been done in routine. This practice may prove to be helpful in reducing the disease burden of TB patients as well as DM patients. Thus it is recommended that the screening for DM should be implemented in TB/DOTS clinics.
Emergence of Multi drug resistant Mycobacterium tuberculosis is also a serious challenge for clinicians. A very large financial implication in terms of treatment, duration of chemotherapy and spread of MDR TB strains is being faced. Treating MDR TB is more complicated than treating drug sensitive TB. Patients with MDR TB require longer, much more costly treatment and experience higher mortality rates. Such a long time to initiate the treatment is not affordable, thus there is a dire need for some rapid technique like molecular based diagnostics for MDR detection, which can provide quick results and making it possible to start treatment at earlier to minimize transmission, morbidity and mortality.
Availability: Items available for loan: UVAS Library [ Call number: 2710-T] (1).