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Volume 18, Number 2—February 2012
Letter

Leishmania infantum and Human Visceral Leishmaniasis, Argentina

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Figure A1

Thumbnail of Incidence of visceral leishmaniasis (VL) in northern Argentina. Map at left indicates location of study area (right). Circle indicates location of farm where the patient (44-year-old man) in this study worked. Light green area indicates dry Chaco region, where VL is endemic and human cases have been found.

Figure A1. Incidence of visceral leishmaniasis (VL) in northern Argentina. Map at left indicates location of study area (right). Circle indicates location of farm where the patient (44-year-old man) in this study worked....

To the Editor: In Argentina, 14 autochthonous human cases of visceral leishmaniasis (VL) were reported during 1925–1989. These cases occurred in different localities in Salta, Jujuy, Santiago del Estero, and Chaco Provinces of northwestern Argentina (Figure A1), where cutaneous leishmaniasis (CL) caused principally by Leishmania (Viannia) braziliensis is endemic.

It had been postulated that scattered/sporadic VL cases could be caused by visceralization of dermatrophic Leishmania spp. because of 1) absence of already recognized L. (Leishmania) infantum vector species; 2) geographic overlap with the region where CL is endemic; 3) simultaneous symptoms of CL; or 4) lack of detailed parasitic characterization at the molecular level for cases of suspected VL (1). However, during recent decades, urban outbreaks of VL have spread to southern regions of South America (Mato Grosso do Sul, Brazil, and Asunción, Paraguay) near the northern border with Argentina.

In May 2006, an autochthonous human case of VL was reported in Posadas (northeastern Argentina); it was associated with the canine visceral form of the disease. In addition, the presence of Lutzomyia longipalpis sandflies was also reported (2). Currently, 58 human VL cases have been reported in Posadas (3), and >7,000 infected dogs, Lu. longipalpis sandflies, and canine VL have been found 350 km south of Posadas (4).

During 2007–2008, new VL cases in 4 children and 7 dogs were reported clustering in time and space in La Banda-Santiago del Estero in the dry Chaco region of Argentina. This focus showed a different pattern from that found in the only urban outbreak of VL reported (nearly the same number of cases in humans and dogs, and the suspected vector was Lu. migonei sandflies instead of Lu. longipalpis sandflies) (5).

We report a case of autochthonous human VL in Salta Argentina that was caused by L. (L.) infantum. This parasite was characterized by cytochrome b (cytb) gene sequencing. Sequencing of this gene has been validated for precise characterization of Leishmania spp (6,7).

On September 9, 2009, a 44-year-old man from Salta, Argentina (Figure A1), was admitted to the Infectious Disease Service at Hospital Señor del Milagro in Salta. The patient had fever, weight loss, dyspepsia, and splenomegaly that evolved over 3 weeks. Physical examination showed cutaneous and mucosal paleness. His general condition was feverish and rapidly deteriorating.

Laboratory tests at the time of final diagnosis showed anemia, leukocytopenia, thrombocytopenia, and increased levels of lactate dehydrogenase. Results of urinalysis and coproculture were negative for parasites. Electrophoresis of serum proteins showed increased levels of gamma globulins. The differential diagnosis was negative for malaria, mycosis, autoimmune hepatitis, and lymphoma. A bone marrow smear showed abundant amastigotes by Giemsa staining (Figure, panel A). The patient was treated with liposomal amphotericin B, 3 mg/day for 7 days, and recovered (8).

After a comprehensive interview, we verified that this patient had not been in the VL-endemic area in Argentina. However, he had worked (deforestation activities) during January–February 2009 on a farm in Finca Las Maravillas (22º3′29.30″S, 63º14′28.17″W), where he had been bitten by phlebotomines and acquired the disease. This farm was situated in the dry Chaco region near the border with Bolivia and Paraguay (zones with VL) (9), a region with intensive deforestation and agricultural activities.

For species identification, DNA was extracted from a bone marrow aspirate and peripheral blood. We amplified by nested PCR and sequenced the cytb gene (Figure, panel B) (6). The aligned 817-bp sequence obtained showed 100% homology with the cytb gene of the MHOM/TN/80/IPT1 L. (L.) infantum World Health Organization reference strain (Tunisian strain) and 99.3% homology with the MHOM/BR/74/PP75 L. (L.) chagasi strain (Brazilian strain) (7).

L. (L.) infantum was identified as the causative agent of this VL case in Salta, Argentina, where VL cases had not been seen for 50 years. Our findings indicate that this case was not caused by visceralization or a dermatropic Leishmania spp. We suggest that the scattered pattern of VL incidence in the dry Chaco region is caused by an enzootic cycle with accidental human transmission (5).

There are no reports of Lu. longipalpis sandflies in the study area or surrounding areas (10). Nevertheless, studies on natural infections of vector sandflies and reservoir-host animals (especially dogs) are needed. Therefore, the search for naturally infected sandflies and reservoirs of this infection should be intensified. Epidemiologic surveys of dogs are needed to identify spread of VL foci in areas of deforestation. Deforestation could alter vector and reservoir range and parasite density in the enzootic cycle and increase human exposure to infected vectors.

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Acknowledgments

We thank Servicio de Enfermedades Infecciosas-Hospital Señor del Milagro, Salta, Argentina, and Noemí Dávalo for support during the clinical phase of the study; Jesús Sajama for drawing the map; and Rubén Cardozo for conducting field research.

This study was supported in part by the El Consejo de Investigación de la Universidad Nacional de Salta and Comisión Nacional Salud Investiga-Ministerio de Salud de la Nación, Argentina.

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Alejandra BarrioComments to Author , Cecilia M. Parodi, Fabricio Locatelli, María C. Mora, Miguel A. Basombrío, Masataka Korenaga, Yoshihisa Hashiguchi, María F. García Bustos, Alberto Gentile, and Jorge D. Marco

Author affiliations: Universidad Nacional de Salta, Salta, Argentina (A. Barrio, C.M. Parodi, M.C. Mora, M.A. Basombrío, M.F. García Bustos, J.D. Marco); Kochi Medical School, Kochi, Japan (F. Locatelli, M. Korenaga, Y. Hashiguchi); Ministerio de Salud Pública-Provincia de Salta, Salta (A. Gentile)

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References

  1. Martín-Sánchez  J, Navarro-Mari  JM, Pasquau-Liaño  J, Salomón  OD, Morillas-Márquez  F. Case report. Visceral leishmaniasis caused by Leishmania infantum in a Spanish patient in Argentina: what is the origin of the infection? BMC Infect Dis. 2004;4:20. DOIPubMed
  2. Salomon  O, Sinagra  A, Nevot  M, Barberian  G, Paulin  P, Estevez  J, First visceral leishmaniasis focus in Argentina. Mem Inst Oswaldo Cruz. 2008;103:10911. DOIPubMed
  3. Cruz  I, Acosta  L, Gutiérrez  MN, Nieto  J, Cañavate  C, Deschutter  J, A canine leishmaniasis pilot survey in an emerging focus of visceral leishmaniasis: Posadas (Misiones, Argentina). BMC Infect Dis. 2010;10:342. DOIPubMed
  4. Fernández  MS, Salomón  OD, Cavia  R, Perez  AA, Acardi  SA, Guccione  JD. Lutzomyia longipalpis spatial distribution and association with environmental variables in an urban focus of visceral leishmaniasis, Misiones, Argentina. Acta Trop. 2010;114:817. DOIPubMed
  5. Salomón  OD, Quintana  MG, Bezzic  G, Moránc  ML, Betbederc  E, Valdéz  DV. Short communication: Lutzomyia migonei as putative vector of visceral leishmaniasis in La Banda, Argentina. Acta Trop. 2010;113:847. DOIPubMed
  6. Myint  CK, Asato  Y, Yamamoto  Y, Kato  H, Bhutto  AM, Soomro  FR, Polymorphisms of cytochrome b gene in Leishmania parasites and their relation to types of cutaneous leishmaniasis lesions in Pakistan. J Dermatol. 2008;35:7685. DOIPubMed
  7. Foulet  F, Botterel  F, Buffet  F, Morizot  G, Rivollet  D, Deniau  M, Detection and identification of Leishmania species from clinical specimens by using a real-time PCR assay and sequencing of the cytochrome b gene. J Clin Microbiol. 2007;45:21105. DOIPubMed
  8. Rosenthal  E, Delaunay  P, Jeandel  PY, Haas  H, Pomares-Estran  C, Marty  P. Liposomal amphotericin B as treatment for visceral leishmaniasis in Europe, 2009. Med Mal Infect. 2009;39:7414. DOIPubMed
  9. Bastrenta  B, Mita  N, Buitrago  R, Vargas  F, Flores  M, Machane  M, Human mixed infections of Leishmania spp. and LeishmaniaTrypanosoma cruzi in a sub-Andean Bolivian area: identification by polymerase chain reaction/hybridization and isoenzyme. Mem Inst Oswaldo Cruz. 2003;98:25564. DOIPubMed
  10. Salomón  OD, Rosa  JR, Stein  M, Quintana  MG, Fernández  MS, Visintin  AM, Phlebotominae (Diptera: Psycodidae) fauna in the Chaco region and cutaneous leishmaniasis transmission patterns in Argentina. Mem Inst Oswaldo Cruz. 2008;103:57884. DOIPubMed

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DOI: 10.3201/eid1802.110924

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Table of Contents – Volume 18, Number 2—February 2012

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Alejandra Barrio, Cátedra de Microbiología y Parasitología, Facultad de Ciencias de la Salud, Universidad Nacional de Salta, Avenida Bolivia 5150, CP 4400 Salta, Argentina

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Page created: January 12, 2012
Page updated: January 12, 2012
Page reviewed: January 12, 2012
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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