SHORT COMMUNICATION- Lutzomyia longipalpis in Clorinda, Formosa province, an area of potential visceral leishmaniasis transmission in Argentina

Abstract

Phlebotomine captures were performed during 2004 in Clorinda, Argentina. Clorinda is located across the branches of the Paraguay river in front of Asunción city, Paraguay. Reports of canine and human visceral leishmaniasis in Asunción have been increasing since 1997, however neither leishmaniasis cases nor sand flies were ever recorded from Clorinda. Light traps were located in migration paths (bridges, port), and peridomestic environments of Clorinda and surrounding localities. Lutzomyia longipalpis was found in Clorinda and Puerto Pilcomayo, first report in a potential visceral leishmaniasis transmission area for Argentina. Active surveillance is required immediately in the localities involved and the surrounding area.

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475Mem Inst Oswaldo Cruz, Rio de Janeiro, Vol. 100(5): 475-476, August 2005
SHORT COMMUNICATION
Lutzomyia longipalpis in Clorinda, Formosa province, an area of
potential visceral leishmaniasis transmission in Argentina
Oscar D Salomón/+, Pablo W Orellano*
Centro Nacional de Diagnóstico e Investigación en Endemo-Epidemias, CeNDIE-ANLIS, Ministerio de Salud y Ambiente de la
Nación, Av. Paseo Colón 568, 1263, Buenos Aires, Argentina *Programa de Residencia en Epidemiología de Campo, Ministerio de
Salud y Ambiente de la Nación, Buenos Aires, Argentina
Phlebotomine captures were performed during 2004 in Clorinda, Argentina. Clorinda is located across the
branches of the Paraguay river in front of Asunción city, Paraguay. Reports of canine and human visceral leishma-
niasis in Asunción have been increasing since 1997, however neither leishmaniasis cases nor sand flies were ever
recorded from Clorinda. Light traps were located in migration paths (bridges, port), and peridomestic environ-
ments of Clorinda and surrounding localities. Lutzomyia longipalpis was found in Clorinda and Puerto Pilcomayo,
first report in a potential visceral leishmaniasis transmission area for Argentina. Active surveillance is required
immediately in the localities involved and the surrounding area.
Key words: Lutzomyia longipalpis - visceral leishmaniasis - Argentina
Fourteen cases of autochtonous leishmaniasis with
visceral involvement were recorded in Argentina from 1925
to 1989 scattered in time and space (Salomón et al. 2001).
Since then two cases of visceral leishmaniasis (VL) with
parasite characterization were reported, but one was im-
ported from Brazil (Nocito et al. 2002), and the other from
Spain (Martín-Sánchez et al. 2004). Further, Lutzomyia
longipalpis (Lutz & Neiva, 1912), the known vector of VL
in the New World (Le Pont & Desjeux 1985, Lainson &
Rangel 2003) was not found in the captures performed in
the six provinces that reported the 14 cases mentioned
above (Salomón 2003). In Misiones province scarce indi-
viduals of Lu. longipalpis were captured in 1951 and again
in 2000 in two places close each other, but no cases of VL
have been ever reported there (Salomón et al. 2001). On
the other hand, VL canine seroprevalence in Asunción
area, Paraguay, ranged from 3.1 to 11.8% between 1997
and 1999 (Canese 2000), while human VL reported cases
from the same area rose from 9 in 2003 to 41 in 2004 (Canese
A, pers. commun.). Clorinda city (25º17’S, 57º43’W, 47,000
inhabitants), in Formosa province, is located in front of
Asunción City on the Pilcomayo-Paraguay river interna-
tional border. Therefore, phlebotomine sandflies captures
were performed during 2004 in Clorinda in order to assess
the presence of Lu. longipalpis and the risk of VL trans-
mission.
Phlebotomine captures were performed with minilight
traps CDC like overnight in Clorinda city, Puerto
Pilcomayo, Laguna Blanca-Parque Pilcomayo (60 km west
of Clorinda), “Km 1254” and “Km 1264” (60 and 50 km
south of Clorinda respectivelly). Eleven sites were sampled
between 7 and 11 June 2004, and 18 sites between 16-21
December 2004, at least two nights each site in both peri-
ods. The capture sites were selected within peridomestic
habitats with close vegetation, animal dwellings and/or
proximity to the border with Paraguay. The phlebotomine
were cleared, mounted and identified as already published
(Salomón et al. 2002)
Seven individuals (4 males, 3 females) of Lu. lon-
gipalpis were captured in peridomestic pig pens of Puerto
Pilcomayo (“Km 9” and “Km 11 1/2”). Besides, 3 males of
Lu. longipalpis were collected in Clorinda peridomiciles
(Libertad street 30 m from the river and Porteño Norte
neighbourhood). One male of Lu. longipalpis was trapped
in June, the remainder sand flies were caught in Decem-
ber. Despite the low densities found, this is the first report
of a competent vector of VL in Argentina close to a cur-
rent VL focus, and Formosa the second province ever
reported with Lu. longipalpis in the country.
Lu. cortelezzii (12 individuals), Lu. shannoni (1), and
Lu. neivai (4) were also found in Clorinda and Puerto
Pilcomayo capture sites, but no sand flies were collected
in the surrounding southern or western villages. Lu. neivai
is the prevalent species in tegumentary leishmaniasis foci
of Formosa province (Salomón et al. 2002).
In conclusion, there is a potential risk of VL transmis-
sion in Clorinda due to: i) the presence of Lu. longipalpis
in Clorinda close to populated areas, ii) the reports of VL
from the ‘Great Asunción’ in Paraguay, and iii) the fluent
movement of individuals, bought and stray dogs along
the border. Thus, an active surveillance system is required
immediately in the area in order to improve the local ca-
pacities on detection and diagnose both human and ca-
nine leishmaniasis. The transit of stray dogs in the fron-
tier should be controlled as in any other dog related
+Corresponding author. E-mail: danielsalomon@hotmail.com
Received 15 February 2005
Accepted 11 July 2005

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476Lu. longipalpis in Clorinda, Argentina • OD Salomón , PW Orellano
zoonotic scenario. Finally with the aim to evaluate changes
in the space-time distribution of the risk a regular moni-
toring of phlebotomine at strategic places would be per-
formed.
ACKNOWLEDGEMENTS
To Ministerio de Salud y Ambiente de la Nación, Ministerio
de Desarrollo Humano de la Provincia de Formosa, and
Fundación Mundo Sano for providing valuable cooperation,
field facilities and technical assistance.
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