polymerase chain reaction (PCR) methods (Chayaburakul et al.,
2004; Anantasomboon et al., 2006). Most significantly, multiple
spheroids were observed in the lymphoid organs and shown to
contain several viruses of known and unknown types (Anantasomboon
et al., 2006; Sritunyalucksana et al., 2006). Hepatopancreatic
cells of affected shrimp sometimes also showed the presence of
inclusions of monodon baculovirus (MBV), hepatopancreatic parvovirus
(HPV) or a currently unidentified microsporidian.