impaginato piccolo - Società Italiana di Parassitologia (SoIPa)

Parassitologia 50: 113-115, 2008
Importance of Aedes albopictus in Veterinary Medicine
M. Pietrobelli
Department of Experimental Veterinary Science, Faculty of Veterinary Medicine, University of Padua, Italy.
Introduction
Abstract. To assess the role of Aedes albopictus in transmission of filarial nematodes of veterinary importance,
researches were carried out in different geographical areas. In Italy a first research was performed
to study the susceptibility of Ae. albopictus to Dirofilaria repens, D. immitis and Setaria labiatopapillosa. The
development of L3 larvae was longer than in other species of mosquitoes but Ae. albopictus could be a suitable
vector of filariae. To understand the role of Ae. albopictus in the natural transmission of Dirofilaria and
to assess the risk for animal and human health, in 2000, 2001 and 2002 another study was carried out in
the town of Padua. A total of 2,534 Ae. albopictus were caught on human-attracted mosquitoes. Specific
primers and sequencing identified filarial DNA as D. immitis; Ae. albopictus was proved a natural vector of
D. immitis. Similar results were confirmed in Central Italy also for D. repens. The presence of Ae. albopictus
increased the probability of transmission of canine and human dirofilariosis in urban environment and it
could change the epidemiology of dirofilariosis, in particular for what concern the time of biting and the risk
season. These aspects must be considered to outline a correct prophylaxis.
Keywords: Aedes albopictus, cattle, dog, Dirofilaria spp., Setaria labiatopapillosa
Aedes albopictus (Skuse)(Diptera: Culicidae), the
“tiger mosquito” which was imported in Italy in 1990
by shipping trade of used tires, is a very aggressive biting
nuisance mosquito species. It received international
attention for its importance in public health as a possible
vector of arboviruses (for at least 22), causing
infectious diseases like Dengue, Yellow Fever,
Encephalites (Mitchell, 1995; Gratz, 2004) and
Chikungunya, recently diagnosed in Italy (Emilia-
Romagna Region)(Dottori et al, 2008).
What is the importance of Ae. albopictus in Veterinary
Medicine? Is this mosquito a potential vector for parasites
of veterinary importance? To assess its role in
transmission of filarial nematodes, in the past some
researches were carried out in different geographical
areas. Concerning Dirofilaria immitis, it has been
demonstrated a high degree of variability ranging from
complete refractoriness to the infection (Apperson et
al, 1989) to partial susceptibility (Konishi, 1989). In
1995 Comiskey and Wesson found first-stage
Dirofilaria larvae infecting the Malpighian tubules in 3
of 163 Ae. albopictus collected from New Orleans
(USA) and in 1999 Nayar and Knight found, 15 days
after infection, the infective L3 stage in 10.9% of Ae.
albopictus (number of L3 larvae ranged from 1 to 37)
and demonstrated that Ae. albopictus is a potential
vector of D. immitis in Florida, U.S.A.The spreading of
Ae. albopictus in Italy raises questions on its possible
role as a vector for indigenous filarial species, common
Correspondence: Mario Pietrobelli
Department of Experimental Veterinary Science,
University of Padua, Viale dell'Università 16
35020 Legnaro (PD)
e-mail: mario.pietrobelli@unipd.it
in dogs (genus Dirofilaria), cattle, equines, pigs and
wild ruminants (genus Setaria). Cancrini et al (1995)
studied the susceptibility of an Ae. albopictus colony
(collected in Civitavecchia, Central Italy) to D. repens,
D. immitis and Setaria labiatopapillosa. Females of Ae.
albopictus were artificially infected with a blood meal
either on dog or on artificial membrane feeders.
Mosquitoes were killed and frozen at various day-interval
after feeding and then dissected. The development
of L3 larvae (about 18 days after infection) was longer
than in other species of mosquitoes but it was demonstrated
that Ae. albopictus can be a suitable vector of
D. repens, D. immitis and S. labiatopapillosa. Few
data are available on the involvement of the “tiger mosquito”
in the natural transmission of filariae. Ahid and
Lourenco-De-Olivera (1999) reported the absence of
D. immitis in specimens collected in an endemic area
of Brazil, whereas Lai et al. (2001) found D. immitis
infected mosquitoes in a Taiwan endemic area.
Materials and methods
To understand the role of Ae. albopictus in the natural
transmission of Dirofilaria and to assess the risk that its
presence might represent for animal and human health, a
study was carried out in the town of Padova by Cancrini
et al (2003) where there is an high mosquito density and
the presence of Dirofilaria nematodes (Capelli et al,
1996). Three areas of the town were checked for the
presence of Ae. albopictus: the garden of the Psychiatric
Hospital (located in the outskirts), an Urban Park and the
Botanical Garden (both located in the centre of the city).
Mosquito sampling was carried out during summer 2000
(10 sampling-days), 2001 (12 sampling-days) and 2002
(5 sampling-days) by two humans used as bait to attract
mosquitoes. Collections were made from 9.00 to 11.00
am and/or from 5.00 to 7.00 pm by aspirating females
landed on the baits with a paper cup aspirator (Coluzzi