Outbreak evaluation of highly pathogenic avian influenza in Bangladesh

Abstract

Bangladesh first experienced outbreaks of highly pathogenic avian influenza (HPAI) subtype H5N1 in poultry 2007 and by December 2012 a total of five hundred fifty six (556) outbreaks have been reported of which four hundred ninety nine (499) outbreaks occur in commercial poultry farm as against only fifty seven (57) in backyard poultry chicken. The virus appeared to be a deadly pathogen causing a total of six hundred eight (608) human cases with three hundred fifty nine (359) deaths in the world. In Bangladesh seven (7) human cases have been reported with a singular mortality of a child acquiring the infection from household poultry. There had been six epidemic waves of AI outbreaks in Bangladesh since March 2007 and other new waves seem to have started. From the six year’s incidence analysis it was found that higher number of outbreaks occurred in the month of February followed by March. The outbreak started from the middle to late winter and continued up to summer. The phylogenetic analysis of viruses isolated till 2010 revealed only one clade 2.2 virus circulating in Bangladesh. But from 2011 two new clades 2.3.2 and 2.3.4 viruses have been introduced. In 2012, it was observed that Clade 2.2 viruses that was in circulation since 2007 were replaced by 2.3.2.1 viruses. Extensive backyard poultry including a large number of ducks, dense human population, and economic dependence of poor people on poultry with low awareness about risk of infection, live bird trading and poor bio-security were critical factors in the spread of avian influenza infection that posses key challenge in rapid containment. Because of the complex situation in poultry production and marketing system, attempts to control this disease through stamping out and bio-security measures have apparently failed in Bangladesh.Bangladesh J. of Livestock Res. 19(1-2): 44-49, Jan-Dec 2012

Antiviral activities of Cholistani plants against common poultry viruses

“…Every year these viruses are causing great economic loss and affecting the trade of poultry all over the world (Okwor et al, 2011;Aslam et al, 2016;Sae Silva et al, 2016). Extensive poultry farming, dense human population, lack of education, a high risk of infection and poor biosecurity measures are common factors in spread of viral diseases in Southeast Asian, North African and Middle East countries (Premnathan et al, 1992;Giasuddin et al, 2012;Lee et al, 2012;Li et al, 2016). Although extensive vaccination campaigns were introduced to control viral outbreaks but still these diseases are uncontrolled in different parts of the world especially in Pakistan.…”

Myxovirus resistance (Mx) Gene Diversity in Avian Influenza Virus Infections

“…An outbreak of HPAI first occurred in Bangladesh in 2007, and since then outbreaks have continued to occur across the country and were mostly reported from commercial chickens ( n = 499) rather than indigenous chickens ( n = 57) [ 9 ]. Some host factors might have been responsible for the lower occurrences of HPAI in indigenous poultry in Bangladesh.…”

“…An outbreak of HPAI occurred in Bangladesh in March 2007 causing the influenza virus to spread to different parts of the country [ 6 , 7 , 8 , 9 ] and to become endemic [ 10 ]. Continuous culling of infected chickens (estimated to be more than 250 million) caused an increase in food insecurity and slowed the economic growth [ 11 , 12 , 13 ].…”

Prevalence and Distribution of Avian Influenza Viruses in Domestic Ducks at the Waterfowl-Chicken Interface in Wetlands

“…During this period, Bangladesh had reported a total of 8 H5N1 outbreaks in poultry. Winter is considered favorable season for AI occurrence and higher presence of IAVs was recorded in Bangladesh and Southeast Asia in winter months [ 49 ]. The long-term persistence of IAVs in the environment, cold water (up to 207 days at 17 °C) and a low relative humidity of 20–35% may explain the higher AI prevalence in winter [ 50 ].…”