Currently, the global economic crisis in
major importing countries, such as the United
States of America (USA), Japan and the European
Union (EU) has seriously affected shrimp prices
and caused declining consumption, whilst shrimp
production has increased tremendously from both
Asia and Latin America. In order to maintain
competitiveness in this business, most small-scale
shrimp farmers reduce the cost of production by
stopping the use of any chemicals for water
treatment to eliminate potential intermediate hosts
or carriers of most diseases prior to stocking PL
into the growout ponds. Thus, shrimp may be
prone to microsporidian infection, particularly in
areas where microsporidian outbreaks have
previously occurred. The objectives of this study
were to evaluate the prevalence of microsporidan
infection in the genus Thelohania (Agmasoma) and
its effects on the growth and histopathological
changes of pond-reared L. vannamei.