-
Foot-and-mouth disease (FMD), a highly contagious viral disease affecting primarily cloven-hoofed animals, continues to be a major concern for the world livestock industry. At one time or another, this menace occurs in most parts of the world including Pakistan, often causing epidemics in cattle, buffaloes and swine. Sheep, goats and many species of wildlife are also susceptible. FMD mortality is usually low but its morbidity is high. Mortality in young calves may be as high as 70 % but in adults it is seldom higher than 5 %. The virus mainly enters the body either by inhalation (droplets) or ingestion (contaminated food). There are seven distinct types of FMD virus viz A, O, C, Sat-1, Sat-2, Sat-3 and Asia-1. The virus is highly mutating leading to constant emergence of new subtypes. The virus is found in blood, milk and saliva soon after infection. Animals of wild origin may act as carrier or reservoir, e.g. dogs, cats, deer, wild boars and even humans, birds and flies[10].
It is important to know the prevalence of major transboundary animal diseases like foot and mouth disease so that a national policy can be determined to control these diseases. A review by Kesy[5], concludes FMD is currently present worldwide. In 2000, fifty nine countries officially reported outbreaks of FMD but there is very little data available from Pakistan. Also the data which was available is based on complement fixation test (CFT) which is non-specific[2] so the data given in this study is much more reliable and authentic and also covers a wider range of areas all over the country.
If we consider the occurrence of FMD in Pakistan, according to Perez et al.[9] method, the estimated probability of an FMD outbreak per 25 km2 cell would be ranged from 0.017 to 0.812, with a range of 47.8 fold (0.812/0.017). The Punjab region would be most likely to have an outbreak.
In view of the importance of FMD, the data of five years (2005-2009) has been gathered and analysed to establish the occurrence of FMDV serotypes in different areas of the country.
HTML
-
A total of 590 epithelial samples collected over a period of five years were analyzed for the presence of FMD (2005-2009). Out of these samples, 180 were found positive for FMDV, giving an overall occurrence of about 33.2 %. Of the prevalent serotypes, 'O' type FMDV accounted for the most outbreaks (20.7 %), followed by A virus type (6.6 %) and Asia-1 virus type (4.6 %) while there was no positive case for type 'C' (Table 1 and 2). The study showed clearly that frequency of the disease was more in the agro-climatic zones and less in hilly areas (Fig. 1).
Table 1. Province-wise FMD serotypes confirmed from outbreaks of 2005-2007
Figure 1. Comparison of FMD outbreaks in hilly and agro-climate areas.Hilly, darker grey; Agro-Climate, lighter grey.
Based on the data of 590 samples ( > 50 outbreaks), the overall prevalence of FMDV in cattle and buffaloes in Pakistan was 33.2 % while it was higher in cattle (37.1 %) than buffalo (28.7 %) (Table 3). There were eight cases of mixed serotype infection. There was an indication of serotype shift when we divided the data into two phases. In phase-Ⅰ (2005-2007), there was an overall prevalence of 29.4%, while the occurrences of the serotypes O, A and Asia-1 were 20.4 %, 2.9 % and 4.7 %, respectively (Table 1). During the phase-Ⅱ (2008-2009), there was an overall prevalence of 59.2 %, while the occurrence of the serotypes O, A and Asia-1 were 22.4 %, 31.6 % and 4.0 %, respectively (Table 2).
Table 2. Area-wise FMD serotypes confirmed from outbreaks of 2008-2009
Table 3. Specie-wise prevalence of FMD virus