Comparative Parasitology 67(2) 2000 - Peru State College

Table 2. Presence of Hymenolepis nana in necropsied
rats, mice, and hamsters.
No. of No. (%) of
individuals individuals Mean
Host species necropsied infected intensity
Golden hamster
Domestic mouse
Norway rat
39
72
38
4 (10.3)
16 (22.2)
12 (31.6)*
* One rat was infected with Hymenolepis dimimita.
DLJCLOS AND RICHARDSON—HYMENOLEPIS NANA IN PETS 199
15
14
66
H. nana is approximately 25 days (Hunninen,
1935; Jacoby and Fox, 1984), leading to the conclusion
that animals arrived infected from commercial
vendors or private breeders, rather than
acquiring infection through exposure at pet
stores. Because of the high demand for and
quick turnover rate of rats, mice, and hamsters,
the majority of pet stores surveyed purchased
their rodents from various vendors rather than
relying on in-house breeding programs. In this
study, 7 of the 12 pet stores purchased animals
from 5 different vendors, while the other 5
stores relied on in-house breeding programs or
various suppliers, either private or commercial
sources. Rodents in those 7 vendor-supplied
stores tested positive for H. nana, while only 3
of the other 5 stores revealed positive rodents
(Table 3).
Evidence for direct transmission of H. nana
as the common route of infection in rodents can
be derived from the concomitant presence of H.
dimimita and H. nana within the same rat cage.
Transmission of H. diminuta requires an arthropod
intermediate host (Roberts and Janovy,
2000). Since the same arthropods may serve as
intermediate hosts for both tapeworms, lower
prevalence of H. diminuta and higher prevalence
of H. nana indicate transmission through direct
rather than indirect routes. If H. nana were using
an intermediate host, one would assume the
prevalences of the 2 tapeworms to be nearly
equivalent.
Traditionally, H. nana is considered a tapeworm
of mice (Markell et al., 1999). However,
the public health significance of the higher prevalence
in rats becomes apparent when the type
of pet most often purchased for children is considered.
According to pet store owners, mice are
usually sold as feeder animals, but hamsters and
Table 3. Summary of survey data on Hymenolepis nana in rodents from pet stores in southern Connecticut,
U.S.A.
Pet store Sample
location size
Necropsy animals:]:
Hamden
Wallingford
Meriden
East Haven
North Branford
Fairrield
Orange
Stratford
Naugatuck (a)
Fecal sample||
Naugatuck (b)
Seymore (a)
Seymore (b)
20
17
10
17
15
21
13
18
18
37
23
9
Store prevalence