0001-6002 0001-6002 S0001-60022013000400003 00 07 2013 00 07 2013 55 07 10

Conferencias Magistrales

Enfermedades rickettsiales: ¿Un problema de salud pública en América Latina?

Rickettsial diseases: a public health problem in Latin America?

Márcio Antônio Moreira Galvão, Amanda de Freitas Padilha

Resumen

Para que una enfermedad sea considerada un problema de salud pública, los parámetros epidemiológicos son magnitud, vulnerabilidad y trascendencia. Si se considera sólo magnitud y vulnerabilidad basadas en la incidencia de las enfermedades rickettsiales en América Latina y en la ausencia de una vacuna efectiva contra esta clase de enfermedades, se puede decir que las enfermedades rickettsiales no son una prioridad ni un problema de salud pública. Sin embargo, si se investigan otros parámetros epidemiológicos se puede tener otra visión acerca de estas enfermedades. El objetivo de este trabajo es analizar mediante un estudio histórico retrospectivo, los factores de riego epidemiológicos en las enfermedades rickettsiales, para confirmar nuestra hipótesis sobre su relevancia en salud pública.

]]> Descriptores: salud pública, rickettsiosis, epidemiología.

Abstract

The epidemiologic parameters for a disease to be considered a public health problem are magnitude, vulnerability and transcendence. If you consider only magnitude and vulnerability based on incidence of rickettsial diseases in Latin America and in the absence of an effective vaccine against these kind of diseases, you can say that rickettsial diseases are not priority and are not a public health problem. If you investigate other epidemiologic parameters we can have another vision about the rickettsial diseases. The objective of this paper is to analyze the epidemiologic risk factors in rickettsial diseases by an historic retrospective in Latin America, to confirm our hypothesis of the public health relevance of rickettsial diseases.

Keywords: Public Health; rickettsioses; epidemiology.

In Latin America, human cases of infection by the genus Rickettsia have been described in several countries in the last twenty years. The increase of notification of this kind of rickettsial diseases is the result of implementation of epidemiologic surveillance and too due to the modifications in the environment changing the spatial distribution of these diseases. The introduction of molecular biologic techniques in the investigation of rickettsial diseases has permitted the detection of new species of the genus Rickettsia in vectors, humans and animals. The sequence of conserved genes from amplified regions by PCR permitted the identification of Rickettsiae not cultivated yet. With this strategy was possible to identify new species as the Rickettsia felis. The description of R. felis human cases in Latin America by 2000s opened new perspectives for comprehension of the role performed by new species of Rickettsia in the epidemiology of rickettsioses. In 2000 only three species of Rickettsia were known in South America. In the beginning of this century more seven species were related in this continent, confirming the importance of the introduction of these techniques in rickettsiology area.1 The use of molecular biology helps too to understand better about the geographic distribution of rickettsioses and about the association vector-rickettsia.2

Some countries, such Brazil, have a long history of rickettsioses, while others such as Argentina, have only recently detected these diseases. In Brazil, Rickettsia rickettsii has been described as the agent of Brazilian spotted fever (BSF) transmitted by the tick Amblyomma cajennense since the 1920s.3 In the last 20 years, cases of BSF have been confirmed by immunofluorescence serology and more recently by molecular techniques in the states of Minas Gerais, São Paulo, Rio de Janeiro and Espírito Santo.4 Between 1990 and 2011, Brazil registered 269 deaths due to BSF. During this period the number of confirmed cases in southeast region reached 747 cases, representing 77.2 % of the total of cases of this country. São Paulo was responsible for 45.7 % of these cases and Minas Gerais for 20.2%.5 Cases of cat flea-associated rickettsiosis caused by Rickettsia felis were reported too in Minas Gerais state, 6 with the detection of this bacterium in Ctenocephalides genus fleas by PCR.7

Spotted fever caused by R. rickettsii were identify too in Mexico, Panama, Costa Rica, Colombia and Argentina.2,8 The Argentine cases were described in Jujuy Province in 1999, when six children with fever, rash and a history of recent tick bite were evaluated for rickettsial infections and immunohistochemistry staining of tissues obtained by \autopsy from one fatal case.9 In Panama the description of R. rickettsii re emergence occurred in 2007 after more than fifty years without the description of spotted fever cases.10 In Mexico the first case of spotted fever caused by R. rickettsii was described in 1930. From 1930 to 1950 many cases of this disease were reported in many states.11 The same phenomenon that was seen in Panama was observed too in Mexico with an epidemiologic silence occurred from 1950 till 2005, when new cases of this re emergent disease initiated to happen again.10 Costa Rica registered the first outbreak of rickettsii spotted fever in 1975. After this date several cases were described in this country.12 In Colombia nothing was known or published about rickettsioses since 1937 when a report of an epidemic caused by R. rickettsii was related and named as “Fiebre de Tobia”. In 2007 two fatal cases of R. rickettsii spotted fever were related near the same locality were the disease was reported in the 1930s.13,14 Peru has a long history of epidemic typhus caused by Rickettsia prowazekii (transmitted by body lice), 15 isolated cases of murine typhus, and the detection of R. felis in Ctenocephalides canis fleas, indicating the possibility of human cases of this rickettsiose.

The principal vectors of rickettsioses found in Latin America as in other parts of the world are arthropods like ticks, fleas, lices and mites. The transmission of Rickettsia by the vector is influenced by different factors, including physiologic and ecologic process. These last factors influence the intensity of Rickettsia transmission for humans and animals. Intrinsic and extrinsic factors can affect significantly the competency of these arthropods as agents of rickettsioses. The risk of occurrence of these diseases due to extrinsic factors includes the population level of the arthropods, the susceptibility of the preferential hosts to Rickettsia, the immunity of the host, the genetic variation determined by infectivity of the agent and the environmental relationships. The intrinsic factors related to the vectors are food, physiologic and compartment questions, transovarial and transstadial transformation, the presence of other organisms or pharmacology actives substances, and the time of permanence of the vector in the host.

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The rates of vector infection can variety depending of pathogen virulence, Rickettsia susceptibility, the presence of co-infections and modulation of immune response at the host. The R. rickettsii maintains in general levels of infection lower than 1%.1,16 Although some authors don´t consider difference between endemic and non endemic areas, asserting that the presence of infected ticks cannot be sufficient to produce human disease, the high infestations by ticks in the environment and in the animals can modify this relation.

Conclusions

To judge if rickettsial diseases are an important public health problem or not in Latin America we need to evaluate all these factors related. Summarizing all them by epidemiologic parameters they can be represented by magnitude, spreading potential, vulnerability and transcendence (measured by fatality, severity, social and economic relevance/spatial distribution of the diseases).

If you consider only magnitude and vulnerability based on incidence of rickettsial diseases in Latin America and the absence of an effective vaccine against this kind of disease, you can say that rickettsial diseases are not priority and are not a public health problem. But if you consider the other epidemiologic parameters we can have another vision about the importance of rickettsial diseases. We can try to do it discussing the situation of each rickettsiose of the genus Rickettsia in Latin America.

The spotted fever caused by R. rickettsii is the more severe rickettsiose among the rickettsial diseases in Latin America with a high case-fatality ratio.1 The primary vectors for R. rickettsii in Latin American are ticks from Amblyomma cajennense specie (Mexico, Panama, Costa Rica, Colombia, Argentina e Brazil), Amblyomma aureolatum (Brazil), Amblyomma imitator (Mexico) and Riphicephalus sanguineus (Mexico).8

Rickettsia parkeri is considered an emergent pathogen in Latin America with suspected human cases related in Uruguay17 and Amblyomma triste as vector.18 Brazil also have suspected cases of this rickettsiose described in the south of the country.

]]> The riquetsiose felis caused by Rickettsia felis has the fleas of Ctenocephalides genus as the principal vector. Although the symptoms of this disease are common in other rickettsioses (fever, myalgia, rash and abdominal pain) and can be synonym of mild cases, neurologic symptoms occurred in Brazilian and Mexican cases can traduce the possibility of severity of this disease in some cases.19

The occurrence of epidemic typhus in Latin America caused by Rickettsia prowazekii can be observed in Peru and Mexico.15, 20 This disease is transmitted by the feces of Pediculus humanus corporis. The outbreaks of epidemic typhus are related to social problems as absence of hygiene and extreme poverty. The case fatality ratio of cases without treatment can reach 30%, with a tax of 60% in elderly people.

Rickettsia typhi the agent of endemic typhus occurs in all Latin America having Xenopsylla cheopis as primary vector and Rattus norvegicus as host. The case fatality ratio is lower than 5%. The elimination of infected fleas with the use of insecticides has diminished the number of human cases and the importance of murine typhus as a public health problem.

The analysis presented of the epidemiologic situation of each rickettsiose help us to conclude that rickettsial diseases are an important public health problem in Latin America due their great social and economic impact. At the time the rickettsioses reach poor regions, the association of agglomeration of people to the potential dissemination of the vector originates an increase in the number of cases in a short period of time. The exemplification of this thesis can be demonstrated in Brazil with R. rickettsii and in Peru and Mexico with R. prowazekii. The phenomenon of familial clusters of R. rickettsii spotted fever rickettsiosis has been noted numerous times in Latin America.21 In fact, the simultaneous occurrence of severe febrile illness in more than one patient generally suggests person-to-person or a point-source transmission of infection. Few physicians in USA may be aware that 4.4% of cases of Rocky Mountain spotted fever occur in the household of another case-patient with the disease, a situation that often lends further diagnostic confusion for this illness that can mimic other febrile exanthems, such as dengue, as well as gastrointestinal infection, other abdominal conditions, pneumonia, and meningoencephalitis.

We conclude with the affirmation that the analysis of the spatial distribution of rickettsial diseases besides social/economic impact is fundamental to understand the occurrence and the spread of these diseases in the present moment in Latin America. We can exemplify it affirmation by the re emergence of cases of Brazilian spotted fever in Minas Gerais state, Brazil since 1980 in urban areas. This occurrence suggests the invasion of natural focus of the disease by the man and an expansion of rickettsioses due to a new ecologic reorganization associated to the way of life of a population excluded in the social economic context.22, 23, 24 The presence of ricketsioses focus in areas of urban expansion was first related in São Paulo by 1920, 25 but continues to be a reality now in Latin America as related in Brazil by 1980’s and recently in Costa Rica.26

References

 1. Labruna MB. Ecology of Rickettsia in South America. Ann N Y Acad Sci 2009; 1116:156-166.         [ Links ]

 2. Parola P, Paddock CD, Raoult D. Tick-borne rickettsioses around the world: emerging diseases challenging old concepts. Clin Microbiol Rev 2005; 18:719-756.         [ Links ]

 3. Piza JT. Considerações epidemiológicas e clínicas sobre o tifo exantemático de São Paulo. São Paulo: Sociedade Impressora Paulista 1932; 11-119.         [ Links ]

 4. Galvão MAM, Lamounier JA, Bonomo E, Tropia MS, Rezende EG, Calic SB, et al. Rickettsioses emergentes e reemergentes em uma área endêmica do estado de Minas Gerais, Brasil. Cad Saúde Pública 2002; 18:109-116.         [ Links ]

 5. Brasil. Ministério da Saúde. Tabela de óbitos de febre maculosa. Brasil Grandes regiões e Unidades Federadas 1990-2011. Acessado em 01/04/2013 de http://portal.saude.gov.br/portal/arquivos/pdf/obitos_febre_maculosa_brasil_1990_2011.pdf.         [ Links ]

 6. Raoult D, La Scola B, Enea M, Fournier PE, Roux V, Galvão MA, et al. A flea-associated rickettsia pathogenic for humans. Emerg Infect Dis 2001; 7:73-81.         [ Links ]

 7. Oliveira RP, Galvão MA, Mafra CL, Chamone CB, Calic SB, Silva SU et al. Rickettsia felis in Ctenocephalides spp. fleas, Brazil. Emerg Infect Dis 2002; 8:317-319.         [ Links ]

 8. Labruna MB, Mattar VS, Nava S, Bermudez S, Venzal JM, Dolz G et al. Rickettsioses in Latin America, Caribbean, Spain and Portugal. Rev MVZ Córdoba 2011; 16:2435-2457.         [ Links ]

 9. Ripoll CM, Remondegui CE, Ordonez G, Arazamendi R, Fusaro H, Hyman MJ, et al. Evidence of rickettsial spotted fever and ehrlichial infection in a subtropical territory of Jujuy, Argentina. Am J Trop Med Hyg 1999; 61:350-354.         [ Links ]

 10. Rodaniche EC, Rodaniche A. Spotted fever in Panama: isolation of the etiologic agent from a fatal case. Am J Trop Med 1950; 30:511-517.         [ Links ]

 11. Bustamante ME, Varela G. Una nueva rickettsiosis en Mexico. Existencia de la fiebre manchada americana em los estados de Sinoloa y Sonora. Rev Inst Salub Enferm Trop 1947; 8:3-14.         [ Links ]

 12. Fuentes LG. Primer caso de fiebre de las Montanas Rocosas en Costa Rica, America Central. Rev Latinoam Microbiol 1979; 21:167-172.         [ Links ]

 13. Patino L, Afanador A, Paul JH. A spotted fever in Tobia, Columbia. Preliminary report. Am J Trop Med 1937; 17:639-653.         [ Links ]

 14. Hidalgo M, Orejuela L, Fuya P, Carrillo P, Hernandez J, Parra E, et al. Rocky Mountain Spotted Fever, Colombia. Emerg Infect Dis 2007; 13:1058-1060.         [ Links ]

 15. Olano JP, Ramirez-Prada B, Moscoso B, Watts D, Walker DH. Epidemic typhus outbreaks in Cuzco, Peru. Am J Trop Med Hyg 1998; 59(Suppl):282.         [ Links ]

 16. Magnarelli LA, Anderson JF, Philip RN, Burgdorfer W, Casper EA. Endemicity of spotted fever group rickettsiae in Connecticut. Am J Trop Med Hyg 1981; 30:715-21.         [ Links ]

 17. Diaz IA. Rickettsioses caused by Rickettsia conorii in Uruguay. Ann N Y Acad Sci 2003; 990:264-266.         [ Links ]

 18. Venzal JM, Portillo A, Estrada-Pena A, Castro O, Cabrera PA, Oteo JA. Rickettsia parkeri in Amblyomma triste from Uruguay. Emerg Infect Dis 2004; 10:1493-1495.         [ Links ]

 19. Galvão MAM, Mafra C, Chamone CB, Calic SB, Zavala-Velazquez JE, Walker DH. Clinical and laboratorial evidence of Rickettsia felis infections in Latin America. Rev Soc Bras Med Trop 2004; 37:238-240.         [ Links ]

 20. Castillo F. El tifus en México antes de Zinsser. In: Florescano E, Malvido E, editors. Ensayos sobre la historia de las epidemias en México. México City: Instituto Mexicano del Seguro Social 1982; 1:127-135.         [ Links ]

 21. Galvão MAM, Mafra CL, Moron C, Anaya E, Walker DH. Rickettsiosis of the genus Rickettsia in South America. Ann N Y Acad Sci 2003; 990:57-61.         [ Links ]

 22. Galvão MAM, Dumler JS, Mafra CL, Calic SB, Chamone CB, Walker DH, et al. Fatal spotted fever rickettsiosis, Minas Gerais, Brazil. Emerg Infect Dis 2003; 9: 1402-1405.         [ Links ]

 23. Galvão MAM. A febre maculosa brasileira em Minas Gerais e seus determinantes. 1988. (Dissertação, Mestrado em Saúde Pública). Escola Nacional de Saúde Pública, ENSP/Fundação Oswaldo Cruz, Rio de Janeiro, 1988.         [ Links ]

 24. Galvão MAM. Febre maculosa em Minas Gerais: um estudo sobre a distribuição da doença no Estado e seu comportamento em área de foco peri-urbano. 1996. Tese de Doutorado, Universidade Federal de Minas Gerais, 1996.         [ Links ]

 25. Silva, LJ, Galvão MAM. Epidemiologia das Riquetsioses do gênero Rickettsia no Brasil. Rev Bras Parasitol Vet 2004; 13:197-198.         [ Links ]

 26. Arguello AP, Hun L, Rivera P, Taylor L. A fatal urban case of Rocky Mountain spotted fever presenting an eschar in San Jose, Costa Rica. Am J Trop Med Hyg 2012; 87:345-348.         [ Links ]

]]> 2009 1116 156-166 2005 18 719-756 1932 11-119 2002 18 109-116 Brasil^dMinistério da Saúde 2001 7 73-81 2002 8 317-319. 2011 16 2435-2457. 1999 61 350-354 1950 30 511-517 1947 8 3-14 1979 21 167-172 1937 17 639-653 2007 13 1058-1060 1998 59 282 282 1981 30 715-21 2003 990 264-266 2004 10 1493-1495 2004 37 238-240 1982 1 127-135 2003 990 57-61. 2003 9 1402-1405 1996 2004 13 197-198 2012 87 345-348