Overview of Waterborne Pathogens - Waterborne Pathogens: Detection Methods and Applications - page 15

2.1.1. Adenovirus
Adenovirus consists of double-stranded DNA in a nonenveloped icosahe-
dral capsid with a diameter of 80 nm. It is thought to have a low infectious
dose and cause gastroenteritis, mainly in infants and children. There are
51 antigenic types of human adenovirus, of which 30% are pathogenic to
humans. 8 The majority of these infect the upper respiratory tract and spread
primarily by droplets. Subtypes 40 and 41 are the major cause of gastro-
enteritis. Adenovirus accounts for 5-20% of U.S. hospital admissions for
diarrhea, and it affects primarily young children. 8 The incubation period
typically lasts between 3 and 10 days with illness persisting for up to a week.
Adenovirus has been detected in large numbers in sewage, raw water
sources and treated drinking water. It is exceptionally resistant to disinfec-
tion procedures, even UV treatment. 9 Further information regarding ade-
noviruses can be found in a review article by Jiang. 10
2.1.2. Astrovirus
Astrovirus is a single-stranded RNA in a nonenveloped icosahedral capsid,
with a diameter of 28 nm. It is typically described as rounded with a smooth
margin, and it may have a five- or six-point star motif in the center. How-
ever, the appearance of astrovirus is highly variable, making visual identifica-
tion of this virus particularly challenging.
There are eight different serotypes of human astrovirus, of which the
most common is serotype number one. Over 80% of children between
the ages of 5 and 10 have been found to have antibodies against serotype
number one. The virus causes mainly mild, self-limiting gastroenteri-
tis, lasting two to three days, with a similar length of incubation time.
Although the illness is normally mild, astrovirus is the second most com-
mon viral cause of diarrhea, and it is responsible for 5% of U.S. hospital
admissions for diarrhea. Astrovirus has been detected in water sources
and supplies.
2.1.3. Enteroviruses
The enteroviruses are among the smallest of all viruses, with a diameter of
20-30nm, and they consist of single-stranded RNA in a nonenveloped
icosahedral capsid. They are one of the most common causes of human
infection and are reported to be responsible for 30 million cases annually
in the United States alone. There are many viruses in this group, including
poliovirus and enterovirus, and therefore there is an equally broad range of