Rickettsioses in Latin America, Caribbean, Spain and Portugal Rickettsiosis en América Latina, el Caribe, España y Portugal

Data on genus and infectious by Rickettsia were retrospectively compiled from the critical review literature regarding all countries in Latin America, Caribbean islands, Portugal and Spain. We considered all Rickettsia records reported for human and/or animal hosts, and/or invertebrate hosts considered being the vector. In a few cases, when no direct detection of a given Rickettsia group or species was available for a given country, the serologic method was considered. A total of 13 Rickettsia species have been recorded in Latin America and the Caribbean. The species with the largest number of country confirmed records were Rickettsia felis (9 countries), R. prowazekii (7 countries), R. typhi (6 countries), R. rickettsii (6 countries), R. amblyommii (5 countries), and R. parkeri (4 countries). The rickettsial records for the Caribbean islands (West Indies) were grouped in only one geographical area. Both R. bellii , R. akari , and Candidatus ‘ R. andeane ’ have been recorded in only 2 countries each, whereas R. massiliae , R. rhipicephali , R.monteiroi , and R. africae have each been recorded in a single country (in this case, R. africae has been recorded in nine Caribbean Islands). For El Salvador, Honduras, and Nicaragua, no specific Rickettsia has been reported so far, but there have been serological evidence of human or/and animal infection. The following countries remain without any rickettsial records: Belize, Venezuela, Guyana, Surinam, and Paraguay. In addition, except for a few islands, many Caribbean islands remain without records. A total of 12 Rickettsia species have been reported in Spain and Portugal: R. conorii , R. helvetica , R. monacensis , R. felis , R. slovaca , R. raoultii , R. sibirica , R. aeschlimannii , R. rioja , R. massiliae , R. typhi , and R. prowazekii . Amongst these Rickettsia species reported in Spain and Portugal, only R. prowazekii , R. typhi , R. felis , and R. massiliae have also been reported in Latin America. This study summarizes the current state of art on the rickettsial distribution in Latin America, Caribbean, Spain and Portugal. The data obtained allow a better understanding on rickettsial epidemiology and distribution of vector ecology.


Introduction
The genus Rickettsia includes bacteria of the order rickettsiales in the alpha subdivision of the class Proteobacteria.They are Gram-negative coccobacilli in obligate association with eukaryote cells.A number of species have been identified in various terrestrial arthropods, and more recently in leeches and amoeba (1,2).Traditionally, pathogenic rickettsiae were classified into two groups: the typhus group (TG), composed of Rickettsia prowazekii and Rickettsia typhi, vectored by lice (Pediculus humanus) and fleas, respectively; and the spotted fever group (SFG), composed of more than 20 species mostly vectored by ticks (3).Other rickettsiae have shown antigenic and genetic particularities that preclude their inclusion in either the TG or SFG, such as Rickettsia bellii and Rickettsia canadensis, reported in ticks from the American continent (4,5).With the discovery of a variety of new rickettsiae
During the last decades, there has been an increasing number of new Rickettsia species of unknown pathogenicity, mostly isolated from ticks (8,9).Some of them, previously considered non-pathogenic, were recently shown to be pathogenic to humans, such as the SFG Rickettsia slovaca, Rickettsia aeschlimannii, Rickettsia massiliae, and Rickettsia monacensis in Europe (8,9).In addition, R. parkeri, an 'old' SFG organism first reported in ticks in the 1939 was shown to be pathogenic 65 years later (10).These facts indicate that any novel described Rickettsia from invertebrate hosts, especially ticks, should be regarded as potentially pathogenic for humans.
The aim of this study was to analize and to summarize the rickettsial reports in Latin America, Caribbean, Portugal and Spain.

Data collection
For the present study, retrospective data on bacteria of the genus Rickettsia were compilled from the available literature regarding all countries in Latin America, and Caribean.Efforts were done to gather all available information for each country.Futhermore, for comparison purposes, we also compiled all Rickettsia species that have been reported in Spain and Portugal, since these two countries were responsible for the main colonization of Latin America.We considered all Rickettsia records reported for human and/or animal hosts, and/or invertebrate hosts (e.g., ticks, lice, fleas), which were considered to be the vector associated with the agent.In a few cases, when no direct detection of a given Rickettsia group TG or SFG or species was available for a given country, the indirect detection through serologic-based methods was considered, when this was the only record available.
El objetivo de este trabajo fue el de analizar y resumir los estudios de Rickettsia en Latinoamérica, el Caribe, España y Portugal.

Geographic distribution of Rickettsia.
All available records on rickettsial infection on hosts (humans and animals) and vectors in Latin America and the Caribbean are represented by country, in tables 1-6.Spain and Portugal are presented in table 7.
A total of 13 Rickettsia species have been recorded in Latin America and the Caribbean.The species with the largest number of country confirmed records were Rickettsia felis (9 countries), R. prowazekii (7 countries), R. typhi (6 countries), R. rickettsii (6 countries), R. amblyommii (5 countries), and R. parkeri (4 countries).
Since the rickettsial records for the Caribbean islands were restricted to West Indies, we grouped these records like that they were represented as a single country (Table 6).R. bellii, R. akari, and Candidatus 'R.andeane' have been recorded in      7).Amongst these Rickettsia species reported in Portugal and Spain, only R. prowazekii, R. typhi, R. felis, and R. massiliae have also been reported in Latin America.
Two fatal cases of spotted fever caused by R. conorii have been diagnosed in Brazil, however, patients of these cases were considered to have acquired the infection in Portugal and South Africa, respectively, and then suffered the disease few days after they arrived in Brazil (Table 8).Likewise, one case of R. africae infection was acquired in Africa before the patient returned to Spain.
For El Salvador, Honduras and Nicaragua, although no specific Rickettsia species has been reported so far, there have been serological evidence of human and animal infection by spotted fever and/or typhus group rickettsioses in these countries (Table 4).
According to our compiled data, the following countries remain without any rickettsial records in Central America and South America: Belize, Venezuela, Guayana, Surinam and Paraguay.In addition, except for the Con respecto a El Salvador, Honduras y Nicaragua, aunque hasta ahora no se han reportado específicamente especies de Rickettsia, se han demostrado evidencia serológica de infección humana y/o animal por los grupos de las fiebres manchadas y/o tifus (Tabla 4).
De acuerdo con los datos compilados, los siguientes países no presentan ningún tipo de registro de rickettsias en América Central y América del Sur: Belice, Venezuela, Guyana, Surinam y Paraguay.Además, a excepción de this paper, many of them also remain without records.The geographical distribution of the 13 Rickettsia species that have been identified in Latin America and Caribbean are shown in figure 1.

Analysis of data
Until the end of the last century, only three Rickettsia species were known to occur in Latin America and Caribbean: R. rickettsii, R. prowazekii, and R. typhi.With the increasing use of molecular methods since the 1990s, other Rickettsia species were discovered in the continent, such as R. africae in West Indies (147), and R. felis in Mexico (133) and later in Brazil (59).In this new century, there was a bulk in the study of Rickettsia in Latin America, with the discovery of at least 8 other Rickettsia species in the continent during the last 10 years, mostly associated with ticks: R. amblyommii, R. bellii, R. rhipicephali, R. parkeri, R. massiliae, R. akari, R. monteiroi, and Candidatus 'R.andeanae' (73,93,105,137).
las 10 islas del Caribe de este trabajo, muchas de ellas también permanecen sin registro.La distribución geográfica de las 13 especies de Rickettsia que se han identificado en América Latina y el Caribe se muestra en la figura 1.

Análisis de los datos
Al

Atlantic ocean
Caribbean sea Consindering the three species (R. rickettsii, R. prowazekii, and R. typhi) known to occur in the continent since the first half of the last century, only R. rickettsii, the agent of rocky mountain spotted fever, showed an increased expansion on its distribution area during the last decades.In fact, rocky mountain spotted fever is currently considered a re-emerging disease in Mexico, Central and South America (81,93,112,131).
The occurrence of R. typhi in the American continent has been practically neglected.
Although this agent has been only scarcely reported in a few Latin American countries recently (49,146,184), most rickettsiologists believe that this rickettsia is widely distributed in the continent, together with its main hosts, synantropic rats and their flea Xenopsylla cheopis (185).Finally, the scarce number of recent records of R. prowazekii during the last few decades seems to be a result of decreased prevalence of its main vetcor, the body louse Pediculus humanus (185).Thus, almost all records of R. prowazekii in Latin America refer to the last century.More recent reports of human cases seem to have been restricted to highland areas of Peru, where body louse infestations are still a problem (185).
The significant advance in our knowlegment on rickettsiology during the last decade in Latin America and Caribbean was certainly a result of the increased interest of researchers on this subject in the continent.However, this advance should be considered still very incipient, if we compare the modest list of Rickettsia species and rickettsial diseases of Latin America and Caribbean with the greater lists here reported for the iberian countries, where rickettsiology has had much greater attention from researchers and governmental institutions.Indeed, the list of rickettsial diseases in Latin America will increase during the next years, not only in the countries with previous records, but also, in many of the American countries where Rickettsia has never been reported.A basal condition for this increase is the urgent need of increased capacity of Latin American laboratories to perform diagnosis of Rickettsia, since the absence of rickettsial dieases in such countries might be merely a result of absence of investigations.
El avance significativo del conocimiento sobre rickettsiología durante la última década en Latinoamérica y el Caribe fue sin duda el resultado del gran interés de los investigadores sobre esta materia en el continente.Sin embargo, este avance debería ser considerado todavía muy incipiente, si se tiene en cuenta la modesta lista de especies de Rickettsia y enfermedades rickettsiales de Latinoamérica y el Caribe, comparada con la de España y Portugal, donde la rickettsiología ha tenido mucha más atención de los investigadores e instituciones gubernamentales.De verdad, que la lista de las enfermedades por Rickettsia se incrementarán en Latinoamérica en los próximos años, no solamente en los países con reportes previos, sino en otros donde nunca ha sido reportada.Una condición básica para este incremento es la necesidad urgente de aumentar la capacidad de los laboratorios de Latinoamérica para llevar a cabo diagnóstico de Rickettsia, ya que la ausencia de la enfermedad en estos países podría ser meramente un resultado de la ausencia de investigaciones.

Table 3 .
Infections by Rickettsia in Bolivia, Colombia, Perú and Ecuador.
only 2 countries each, whereas R. massiliae, R. rhipicephali, R.monteiroi, and R. africae have each been recorded in a single country in this case, R. africae has been recorded in nine islands from the West Indies.Eight Rickettsia species have been associated with human diseases in Latin America and massiliae, R. rhipicephali, R.monteiro y R. africae han sido reportados en un solo país.En este caso R. africae ha sido documentada en nueve islas del Caribe.Ocho especies de Rickettsia han sido asociadas con enfermedad humana en Latinoamérica y el Caribe: R. rickettsii agente de etiológico de

Table 6 .
Infections by Rickettsia in Caribbean Islands.Infections by Rickettsia in Spain and Portugal.

Table 8 .
Importated cases of Rickettsia in Latin America and Iberian peninsula.