Bartonellosis in Zamora Chinchipe province in Ecuador

Seroprevalence and risk factors for infection with Bartonella bacilliformis in Loja province, Ecuador

The seroprevalence and epidemiology of Bartonella bacilliformis infection in the Andean highlands of Ecuador is largely unknown. We conducted a sero-epidemiologic survey of 319 healthy children aged 1-15 years living in six rural, mountain communities in Loja Province, Ecuador. Blood was collected by finger stick onto filter paper and dried, and the eluted sera analyzed for antibodies to B. bacilliformis by rPap31 ELISA. Demographic, entomologic, and household variables were assessed to investigate associated risk factors for antibody seropositivity to B. bacilliformis. Seroprevalence of 28% was found among children in the study communities. Increased risk of seropositivity was associated with the presence of lumber piles near houses. Decreased risk of seropositivity was observed with the presence of animal waste and incremental 100 meter increases in elevation. Although investigation of clinical cases of Carrion's disease was not within the scope of this study, our serology data suggest that infection of children with B. bacilliformis is prevalent in this region of Ecuador and is largely unrecognized and undiagnosed. This study highlights the need to further investigate the prevalence, pathogenesis, epidemiology, and disease impact of this pathogen in Ecuador.

Carrion's Disease: the Sound of Silence

Carrion's disease (CD) is a neglected biphasic vector-borne illness related to Bartonella bacilliformis. It is found in the Andean valleys and is transmitted mainly by members of the Lutzomyia genus but also by blood transfusions and from mother to child. The acute phase, Oroya fever, presents severe anemia and fever. The lethality is high in the absence of adequate treatment, despite the organism being susceptible to most antibiotics. Partial immunity is developed after infection by B. bacilliformis, resulting in high numbers of asymptomatic carriers. Following infection there is the chronic phase, Peruvian warts, involving abnormal proliferation of the endothelial cells. Despite potentially being eradicable, CD has been expanded due to human migration and geographical expansion of the vector. Moreover, in vitro studies have demonstrated the risk of the development of antimicrobial resistance. These findings, together with the description of new Bartonella species producing CD-like infections, the presence of undescribed potential vectors in new areas, the lack of adequate diagnostic tools and knowledge of the immunology and bacterial pathogenesis of CD, and poor international visibility, have led to the risk of increasing the potential expansion of resistant strains which will challenge current treatment schemes as well as the possible appearance of CD in areas where it is not endemic.

Bartonella Species, an Emerging Cause of Blood-Culture-Negative Endocarditis

Since the reclassification of the genus Bartonella in 1993, the number of species has grown from 1 to 45 currently designated members. Likewise, the association of different Bartonella species with human disease continues to grow, as does the range of clinical presentations associated with these bacteria. Among these, blood-culture-negative endocarditis stands out as a common, often undiagnosed, clinical presentation of infection with several different Bartonella species. The limitations of laboratory tests resulting in this underdiagnosis of Bartonella endocarditis are discussed. The varied clinical picture of Bartonella infection and a review of clinical aspects of endocarditis caused by Bartonella are presented. We also summarize the current knowledge of the molecular basis of Bartonella pathogenesis, focusing on surface adhesins in the two Bartonella species that most commonly cause endocarditis, B. henselae and B. quintana. We discuss evidence that surface adhesins are important factors for autoaggregation and biofilm formation by Bartonella species. Finally, we propose that biofilm formation is a critical step in the formation of vegetative masses during Bartonella-mediated endocarditis and represents a potential reservoir for persistence by these bacteria.

Oroya fever and verruga peruana: bartonelloses unique to South America

Bartonella bacilliformis is the bacterial agent of Carrión's disease and is presumed to be transmitted between humans by phlebotomine sand flies. Carrión's disease is endemic to high-altitude valleys of the South American Andes, and the first reported outbreak (1871) resulted in over 4,000 casualties. Since then, numerous outbreaks have been documented in endemic regions, and over the last two decades, outbreaks have occurred at atypical elevations, strongly suggesting that the area of endemicity is expanding. Approximately 1.7 million South Americans are estimated to be at risk in an area covering roughly 145,000 km2 of Ecuador, Colombia, and Peru. Although disease manifestations vary, two disparate syndromes can occur independently or sequentially. The first, Oroya fever, occurs approximately 60 days following the bite of an infected sand fly, in which infection of nearly all erythrocytes results in an acute hemolytic anemia with attendant symptoms of fever, jaundice, and myalgia. This phase of Carrión's disease often includes secondary infections and is fatal in up to 88% of patients without antimicrobial intervention. The second syndrome, referred to as verruga peruana, describes the endothelial cell-derived, blood-filled tumors that develop on the surface of the skin. Verrugae are rarely fatal, but can bleed and scar the patient. Moreover, these persistently infected humans provide a reservoir for infecting sand flies and thus maintaining B. bacilliformis in nature. Here, we discuss the current state of knowledge regarding this life-threatening, neglected bacterial pathogen and review its host-cell parasitism, molecular pathogenesis, phylogeny, sand fly vectors, diagnostics, and prospects for control.

Bartonella bacilliformis: a systematic review of the literature to guide the research agenda for elimination

Background

Carrion's disease affects small Andean communities in Peru, Colombia and Ecuador and is characterized by two distinct disease manifestations: an abrupt acute bacteraemic illness (Oroya fever) and an indolent cutaneous eruptive condition (verruga Peruana). Case fatality rates of untreated acute disease can exceed 80% during outbreaks. Despite being an ancient disease that has affected populations since pre-Inca times, research in this area has been limited and diagnostic and treatment guidelines are based on very low evidence reports. The apparently limited geographical distribution and ecology of Bartonella bacilliformis may present an opportunity for disease elimination if a clear understanding of the epidemiology and optimal case and outbreak management can be gained.

Methods

All available databases were searched for English and Spanish language articles on Carrion's disease. In addition, experts in the field were consulted for recent un-published work and conference papers. The highest level evidence studies in the fields of diagnostics, treatment, vector control and epidemiology were critically reviewed and allocated a level of evidence, using the Oxford Centre for Evidence-Based Medicine (CEBM) guidelines.

Results

A total of 44 studies were considered to be of sufficient quality to be included in the analysis. The majority of these were level 4 or 5 (low quality) evidence and based on small sample sizes. Few studies had been carried out in endemic areas.

Conclusions

Current approaches to the diagnosis and management of Carrion's disease are based on small retrospective or observational studies and expert opinion. Few studies take a public health perspective or examine vector control and prevention. High quality studies performed in endemic areas are required to define optimal diagnostic and treatment strategies.

Carrion's disease is one of the truly neglected tropical diseases. It affects children predominantly in small Andean communities in Peru, Colombia and Ecuador. Case fatality rates of untreated acute disease can exceed 80% during outbreaks. Diagnostic and treatment guidelines are based on very low evidence reports and public health and prevention programs have been limited. This paper presents the first systematic review of Carrion's disease in Peru and encompasses a detailed analysis of all the highest level evidence regarding not only diagnosis and management but also vector control and prevention. In the review, the authors highlight the considerable knowledge gaps in this field and suggest a strategy for a renewed effort in its investigation. The authors hope that through this work we will be able to develop a better understanding of the epidemiology, natural history and optimal approaches to case and outbreak

Multi-locus sequence analysis reveals profound genetic diversity among isolates of the human pathogen Bartonella bacilliformis

Bartonella bacilliformis is the aetiological agent of human bartonellosis, a potentially life threatening infection of significant public health concern in the Andean region of South America. Human bartonellosis has long been recognised in the region but a recent upsurge in the number of cases of the disease and an apparent expansion of its geographical distribution have re-emphasized its contemporary medical importance. Here, we describe the development of a multi-locus sequence typing (MLST) scheme for B. bacilliformis and its application to an archive of 43 isolates collected from patients across Peru. MLST identified eight sequence types among these isolates and the delineation of these was generally congruent with those of the previously described typing scheme. Phylogenetic analysis based on concatenated sequence data derived from MLST loci revealed that seven of the eight sequence types were closely related to one another; however, one sequence type, ST8, exhibited profound evolutionary divergence from the others. The extent of this divergence was akin to that observed between other members of the Bartonella genus, suggesting that ST8 strains may be better considered as members of a novel Bartonella genospecies.

Isolation and characterization of Bartonella bacilliformis from an expatriate Ecuadorian

Carrion's disease is typically biphasic with acute febrile illness characterized by bacteremia and severe hemolytic anemia (Oroya fever), followed by benign, chronic cutaneous lesions (verruga peruana). The causative agent, Bartonella bacilliformis, is endemic in specific regions of Peru and Ecuador. We describe atypical infection in an expatriate patient who presented with acute splenomegaly and anemia 3 years after visiting Ecuador. Initial serology and PCR of the patient's blood and serum were negative for Bartonella henselae, Bartonella quintana, and B. bacilliformis. Histology of splenic biopsy was suggestive of bacillary angiomatosis, but immunohistochemistry ruled out B. henselae and B. quintana. Bacilli (isolate EC-01) were subsequently cultured from the patient's blood and analyzed using multilocus sequence typing, protein gel electrophoresis with Western blotting, and an immunofluorescence assay (IFA) against a panel of sera from patients with Oroya fever in Peru. The EC-01 nucleotide sequences (gltA and internal transcribed spacer) and protein band banding pattern were most similar to a subset of B. bacilliformis isolates from the region of Caraz, Ancash, in Peru, where B. bacilliformis is endemic. By IFA, the patient's serum reacted strongly to two out of the three Peruvian B. bacilliformis isolates tested, and EC-01 antigen reacted with 13/20 Oroya fever sera. Bacilliary angiomatosis-like lesions were also detected in the spleen of the patient, who was inapparently infected with B. bacilliformis and who presumably acquired infection in a region of Ecuador where B. bacilliformis was not thought to be endemic. This study suggests that the range of B. bacilliformis may be expanding from areas of endemicity in Ecuador and that infection may present as atypical clinical disease.

Epidemiology of leishmaniasis in Ecuador: current status of knowledge -- a review

Although leishmaniasis is regarded as a significant health problem in Ecuador by the Ministry of Health, and the incidence has increased over the last years, an official map on the geographic distribution of disease and sand fly vectors or a control strategy do not exist yet. This article reviews the current situation based on published information to improve our knowledge and understand the epidemiological situation of leishmaniasis in Ecuador in order to help future research and to develop a national control strategy. The disease is endemic in most provinces throughout Pacific coastal region, Amazonian lowlands, and some inter-Andean valleys with a total 21,805 cases reported during 1990-2003. Whereas cutaneous leishmaniasis (CL) is found throughout Ecuador, mucocutaneous leishmaniasis (MCL) appears to be restricted to the Amazon region; one, parasitologically unconfirmed case of visceral form was reported in 1949. Most human infections are caused by Leishmania (Viannia) spp., which is distributed in the subtropical and tropical lowlands; infections due to L. (Leishmania) spp. are found in the Andean highlands and in the Pacific lowlands as well. The proven vectors are Lutzomyia trapidoi and Lu. ayacuchensis. Canis familiaris, Sciurus vulgaris, Potos flavus, and Tamandua tetradactyla have been found infected with Leishmania spp. It is estimated that around 3000-4500 people may be infected every year, and that 3.1 to 4.5 millions people are estimated to be at risk of contracting leishmaniasis.

Bartonellosis. New and old

The number of species that comprise the family of Bartonellaceae, genus Bartonella, has recently increased from one to 11 species, five of which have been associated with different diseases and syndromes in humans. The rapidly growing number of human pathogens has led several investigators to regard bartonellosis and other associated syndromes as important emerging infectious diseases. This article presents the history and epidemiology, clinical features, diagnosis, and treatment of bartonellosis and associated diseases, including Carrión's disease, trench fever, endocarditis and bacteremia, bacillary angiomatosis, and cat-scratch disease.

An outbreak of bartonellosis in Zamora Chinchipe Province in Ecuador

We report an outbreak of human bartonellosis in Zamora Chinchipe Province in Ecuador, which occurred in 1995-1996. Nineteen cases were seen, of which 18 presented with classical oroya fever (fever and profound anaemia) and one with verruga peruana; 11 of the cases (58%) had positive blood films containing Bartonella bacilliformis. The houses of cases and neighbouring controls were visited; blood samples for thin films and cultures were collected from members of each house and a questionnaire was administered to investigate possible risk factors for disease transmission. In none of those sampled was B. bacilliformis bacteriologically demonstrable. All case houses were located in isolated areas at the margin of forest and the presence of dead rodents was reported only in case houses (P < 0.05). We suggest that human bartonellosis is a zoonosis with a natural rodent reservoir and that migrant humans infected in this way may become a temporary reservoir host in populated areas.