Hepatozoon PCR test for dogs and cats
dog and cat assay data sheet
Hepatozoon species
Test code:
X0029
- Ultrasensitive qualitative detection but not differentiation of
Hepatozoon species by real time polymerase
chain reaction
Hepatozoon is a genus of the
family Hepatozoidae, which consists of over 300 species of obligate
intraerythrocytic parasites. Different
Hepatozoon species have been
described in both vertebrates and invertebrates. Some members of
Hepatozoon genus have very
complex life cycles. For example, an insect may be infected with a
Hepatozoon species. Inside the hemocoel of the insect, sexual
reproduction and sporogenic development occur. When the insect is
subsequently consumed by a vertebrate host, the sporozoites migrate to
the liver of the vertebrate, where they undergo multiple fission
(asexual reproduction) to produce merozoites. The merozoites are then
released into the bloodstream, where they form gametocytes. When
another insect feeds on the blood of the infected vertebrate, the
gamonts are taken up into the gut of the insect, and another life
cycle begins.
In cases when infected vertebrate and invertebrate hosts do not directly
feed on one another, the life cycle is more complicated. For instance,
Hepatozoon sipedon can
infect mosquitoes and snakes, but since snakes do not typically feed
on mosquitoes, a third, intermediate host is required, such as a frog.
The frog captures the infected mosquito, and the snake acquires the
infection by feeding on the now-infected frog. Another mosquito then
feeds on the snake so that another round of the life cycle begins.
In dogs, there are two types of hepatozoonosis, Old World hepatozoonosis
and American canine hepatozoonosis (ACH), which present with distinct
clinical symptoms. Both types are transmitted by ticks, with the Old
World hepatozoonosis transmitted by the brown dog tick,
Rhipicephalus sanguineus, and the ACH transmitted by the Gulf Coast
tick, Amblyomma maculatum.
The Hepatozoon species that
is responsible is also different for the two types of hepatozoonosis -
Hepatozoon canis for the Old World hepatozoonosis, and
Hepatozoon americanum for
ACH. In both cases, the transmission of the hepatozoon is through the
dog’s ingestion of the tick. Dogs infected with
H. canis and
H. americanum can show very
different symptoms. In general, infection with
H. canis leads to only mild
or subclinical symptoms in immunocompetent dogs. Infection with
H. americanum, however, can
result in severe clinical symptoms, with death often occurring within
1–2 years without supportive therapies.
In cats, Hepatozoon infection
is usually subclinical, and infected cats rarely show symptoms of
infection. Although most
Hepatozoon infections in cats are caused by
H. felis, there is also
evidence that H. canis can
infect cats.
Hepatozoons including H. canis, H.
felis, and H. americanum are widely distributed in the world,
although varies in different geographical regions. For example, in one
study, Hepatozoon DNA was found in blood samples of 36% of cats tested
(Baneth et al., 2013), whereas in two other studies conducted in
Portugal, H. felis DNA was detected in blood samples of 15.6% of randomly
sampled cats and 8.6% of owned and shelter cats (Maia et al., 2014;
Vilhena et al., 2013). 13.5% of domestic dogs in Sardinia, Italy, were
found to be positive for H.
canis (Chisu et al., 2023), whereas 0% of domestic dogs in Warsaw
were found to be positive for H.
canis (Zygner et al., 2009). Although the chance of zoonotic
transmission of Hepatozoons from dogs or cats to humans is very low,
caution is still needed when removing ticks from dogs or cats or when
handling infected animals (Kwon et al., 2017).
Current diagnosis of hepatozoonosis relies on clinical symptoms and blood
smear examination. The use of molecular techniques, such as PCR, is
increasingly adopted as the method of choice due to its high
sensitivity and specificity (Otranto et al., 2011).
Utilities:
-
Help confirm the disease causing agent
-
Shorten the time required to confirm a clinical
diagnosis of the infection
-
Early prevention of spread of this parasite among a group of
dogs or cats
-
Help ensure that animal populations are free of this parasite
-
Minimize human exposure to this parasite
-
Safety monitoring of biological products and vaccines that derive
from susceptible animals
References:
Baneth, G. et al. (2013) Redescription of
Hepatozoon felis (Apicomplexa: Hepatozoidae) based on phylogenetic
analysis, tissue and blood form morphology, and possible
transplacental transmission. Parasit Vectors. 6:102. Chisu, V. et
al. (2023) Molecular Survey of Hepatozoon canis Infection in
Domestic Dogs from Sardinia, Italy. Vet. Sci. 10:640. Kwon, S.J. et
al. (2017) First Case of Canine Infection with
Hepatozoon canis
(Apicomplexa: Haemogregarinidae) in the Republic of Korea. Korean J.
Parasitol. 55:561-564. Maia, C. et al. (2014) Bacterial and
protozoal agents of feline vector-borne diseases in domestic and stray
cats from southern Portugal. Parasit. Vectors. 24;7:115. Otranto,
D. (2011) Diagnosis of
Hepatozoon canis in young dogs by cytology and PCR. Parasit.
Vectors. 4:55. Vilhena, H. et al. (2013) Feline vector-borne
pathogens in the north and centre of Portugal. Parasit Vectors. 6:99.
Zygner, W. et al. (2009) Detection of the DNA of
Borrelia afzelii, Anaplasma phagocytophilum and
Babesia canis in blood
samples from dogs in Warsaw. Vet. Rec. 164:465-467.
Preferred specimens: 0.2 ml whole blood in EDTA
(purple top) tube, or 0.2 ml fresh, frozen or
preserved tissue, or whole tick.
Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.
For all specimen types, if there will be a delay in shipping, or
during very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain frozen
in transit. See
shipping instructions for more information.
Turnaround time: 2 business days
Methodology:
Qualitative real time PCR
Normal range: Nondetected
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