Scientific evidence on hepatitis Delta in Brazil: integrative literature review

Integrative literature review, with research in the databases of the Medical Literature Analysis and Retrieval System Online, Latin American and Caribbean Center on Health Sciences Information, Scientific Eletronic Library Online and Scopus, with analysis focusing on the leveling of the methodological rigor according to the model of Melnyk and Fineout-Overholt.

Results:

The search revealed an average of two publications a year between 1987 and 2017. We selected 33 articles, the majority (91%) presented level of evidence VI. The publications were concentrated in the area of tropical medicine (46%) and virology (15%). The authors of 85% of the studies were medical professionals and the most common design was the descriptive/cross-sectional (69.6%).

Conclusion:

Scientific literature on HDV infections in Brazil is focused on prevalence studies, showing incipiency regarding the production of studies with stricter guidelines, such as clinical trials.

Keywords
Hepatitis D; Hepatitis B; Brazil

Escola Paulista de Enfermagem, Universidade Federal de São Paulo R. Napoleão de Barros, 754, 04024-002 São Paulo - SP/Brasil, Tel./Fax: (55 11) 5576 4430 - São Paulo - SP - Brazil
E-mail: actapaulista@unifesp.br

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[1] Corresponding author Marcelo Siqueira de Oliveira Gleba Formoso, Lote 245, 69980-000, Cruzeiro do Sul, AC, Brazil. marcelo.oliveira@ufac.br

Reference	Thematic considerations	Type of study	Evidence level
Souto FJD. A hepatite B e os movimentos migratórios no Estado de Mato Grosso, Brasil. Rev Soc Bras Med Trop. 2004; 37(Suppl 2):63-8.	Literature review on the relation between migratory cycles and the prevalence of hepatitis B and Delta on the north of the state of Mato Grosso - Brazil.⁽²¹21. Souto FJ. A hepatite B e os movimentos migratórios no Estado de Mato Grosso, Brasil. Rev Soc Bras Med Trop. 2004; 37(Suppl 2):63-8.⁾	Literature review	VI
Braga WSM. Infecção pelos vírus das hepatites B e D entre grupos indígenas da Amazônia Brasileira: aspectos epidemiológicos. Rev Soc Bras Med Trop. 2004; 37(Suppl 2):9-13.	Discusses epidemiological aspects of HBV and HDV infection among indigenous groups in Amazon.⁽²²22. Braga WS. Infecção pelos vírus das hepatites B e D entre grupos indígenas da Amazônia brasileira: aspectos epidemiológicos. Rev Soc Bras Med Trop. 2004; 37(Suppl 2):9-13.⁾	Literature review	VI
Braga WSM, Castilho M da C, Borges FG, Leão JRDT, Martinho AC de S, Rodrigues IS, et al. Hepatitis D virus infection in the Western Brazilian Amazon - far from a vanishing disease. Rev Soc Bras Med Trop. 2012; 45(6):691-5.	Investigates the prevalence of HDV infection through the total antibody (Anti-HD).⁽²³23. Braga WS, Castilho M da C, Borges FG, Leão JR, Martinho AC, Rodrigues IS, et al. Hepatitis D virus infection in the Western Brazilian Amazon - far from a vanishing disease. Rev Soc Bras Med Trop. 2012; 45(6):691-5.⁾	Cross-sectional study (descriptive)	VI
Paraná R, Vitvitski L, Pereira JE. Hepatotropic viruses in the Brazilian Amazon: a health threat. Braz J Infect Dis. 2008; 12(3):253-6.	Reviews clinical and epidemiological studies on HBV and HDV infection and their respective genotypes F and III, addressing the existing relation between these and the severity of hepatic disease in the Amazon region.⁽²⁴24. Paraná R, Vitvitski L, Pereira JE. Hepatotropic viruses in the Brazilian Amazon: a health threat. Braz J Infect Dis. 2008; 12(3):253-6.⁾	Study of Literature Review	VI
Braga WSM, Brasil LM, Souza RAB, Castilho MC, Fonseca JC. Ocorrência da infecção pelo vírus da hepatite B (VHB) e delta (VHD) em sete grupos indígenas do Estado do Amazonas. Rev Soc Bras Med Trop. 2001; 34(4):349-55.	Observes the distribution of cases of hepatitis B and D among indigenous ethnic groups in the Western Brazilian Amazon.⁽²⁵25. Braga WS, Brasil LM, Souza RA de, Castilho MC, Fonseca JC. Ocorrência da infecção pelo vírus da hepatite B (VHB) e delta (VHD) em sete grupos indígenas do Estado do Amazonas. Rev Soc Bras Med Trop. 2001; 34(4):349-55.⁾	Cross-sectional study (descriptive)	VI
Braga WSM, Castilho MC, Santos ICV, Moura MAS, Segurado AC. Low prevalence of hepatitis B virus, hepatitis D virus and hepatitis C virus among patients with human immunodeficiency virus or acquired immunodeficiency syndrome in the Brazilian Amazon basin. Rev Soc Bras Med Trop. 2006; 39(6):519-22.	Assesses the prevalence of co-infection among human immunodeficiency virus and viral hepatitis B, C and D in the Western brazilian Amazon.⁽²⁶26. Braga WS, Castilho MC, Santos IC, Moura MA, Segurado AC. Low prevalence of hepatitis B virus, hepatitis D virus and hepatitis C virus among patients with human immunodeficiency virus or acquired immunodeficiency syndrome in the Brazilian Amazon basin. Rev Soc Bras Med Trop. 2006; 39(6):519-22.⁾	Cross-sectional study (descriptive)	VI
Oliveira MLA, Bastos FI, Telles PR, Yoshida CFT, Schatzmayr HG, Paetzold U, et al. Prevalence and risk factors for HBV, HCV and HDV infections among injecting drug users from Rio de Janeiro, Brazil. Braz J Med Biol Res. 1999; 32(9):1107-14.	Assesses the prevalence and the determinants of risk for infections with hepatitis B, C and D among injection drug users in Rio de Janeiro, Brazil.⁽²⁷27. Oliveira ML, Bastos FI, Telles PR, Yoshida CF, Schatzmayr HG, Paetzold U, et al. Prevalence and risk factors for HBV, HCV and HDV infections among injecting drug users from Rio de Janeiro, Brazil. Braz J Med Biol Res. 1999; 32(9):1107-14.⁾	Cross-sectional study (descriptive)	VI
Azevedo RA, Silva AE, Ferraz MLG, Marcopito LF, Baruzzi RG. Prevalência dos marcadores sorológicos dos vírus da hepatite B e D em crianças das tribos Caiabi e txucarramãe do parque indígena do Xingu, Brasil central. Rev Soc Bras Med Trop. 1996; 29(5):431-9.	Studies the prevalence of serological markers of hepatitis B and delta in indigenous children from 0 to 14 years living in the Xingu Indigenous Park.⁽²⁸28. Azevedo RA, Silva AE, Ferraz ML, Marcopito LF, Baruzzi RG. Prevalência dos marcadores sorológicos dos vírus da hepatite B e D em crianças das tribos Caiabietxucarramãe do parque indígena do Xingu, Brasil central. Rev Soc Bras Med Trop. 1996; 29(5):431-9.⁾	Cross-sectional study (descriptive)	VI
Andrade ZA, Lesbordes JL, Ravisse P, Paraná R, Prata A, Barberino JS, et al. Fulminant hepatitis with microvesicular steatosis (a histologic comparison of cases occurring in Brazil - Labrea hepatitis - and in central Africa - Bangui hepatitis). Rev Soc Bras Med Trop. 1992; 25(3):155-60.	Compares cases of fulminant hepatitis in the Western Brazilian Amazon and in Central Africa by associating the HBV and HDV infections.⁽²⁹29. Andrade ZA, Lesbordes JL, Ravisse P, Paraná R, Prata A, Barberino JS, et al. Fulminant hepatitis with microvesicular steatosis (a histologic comparison of cases occurring in Brazil - Labrea hepatitis - and in central Africa - Bangui hepatitis). Rev Soc Bras Med Trop. 1992; 25(3):155-60.⁾	Cross-sectional study (descriptive)	VI
Fonseca JC, Ferreira LCL, Brasil LM, Castilho MC, Moss R, Barone M. Fulminant Labrea hepatitis - The role of hepatitis a (HAV), B (HBV), C (HCV), AND D (HDV) infection. (Preliminary report). Fulminant Labrea Hepat - Role Hepat HAV B HBV C HCV HDV Infect Prelim Rep. 1992; 34(6):609-12.	Describes the participation of HDV infection on the etiopathogenesis of Labrea hepatitis, Western Brazilian Amazon.⁽³⁰30. Fonseca JC, Ferreira LC, Brasil LM, Castilho MC, Moss R, Barone M. Fulminant Labrea hepatitis - The role of hepatitis a (HAV), B (HBV), C (HCV), AND D (HDV) infection. (Preliminary report). Fulminant Labrea Hepat - Role Hepat HAV B HBV C HCV HDV. Infect Prelim Rep. 1992; 34(6):609-12.⁾	Cross-sectional study (descriptive)	VI
Botelho-Souza LF, Souza Vieira D, de Oliveira dos Santos A, Cunha Pereira AV, Villalobos-Salcedo JM. Characterization of the Genotypic Profile of Hepatitis Delta Virus: Isolation of HDV Genotype-1 in the Western Amazon Region of Brazil. Intervirology. 2015; 58(3):166-71.	Assesses the genotypic and clinical characteristics of individuals with the genotype 1 HDV in the Western Brazilian Amazon.⁽³¹31. Botelho-Souza LF, Souza Vieira D, de Oliveira dos Santos A, Cunha Pereira AV, Villalobos-Salcedo JM. Characterization of the genotypic profile of hepatitis delta virus: isolation of hdv genotype-1 in the western amazon region of Brazil. Intervirology. 201519; 58(3):166-71.⁾	Case-control study	IV
Kay A, Melo da Silva E, Pedreira H, Negreiros S, Lobato C, Braga W, et al. HBV/HDV co-infection in the Western Brazilian Amazonia: an intriguing mutation among HDV genotype 3 carriers. J Viral Hepat. 2014; 21(12):921-4.	Studies the genotypic characterization of patients infected with HBV and HDV in the Western Brazilian Amazon.⁽³²32. Kay A, Melo da Silva E, Pedreira H, Negreiros S, Lobato C, Braga W, et al. HBV/HDV co-infection in the Western Brazilian Amazonia: an intriguing mutation among HDV genotype 3 carriers. J Viral Hepat. 2014; 21(12):921-4.⁾	Cross-sectional study (descriptive)	VI
Crispim MAE, Fraiji NA, Campello SC, Schriefer NA, Stefani MMA, Kiesslich D. Molecular epidemiology of hepatitis B and hepatitis delta viruses circulating in the Western Amazon region, North Brazil. BMC Infect Dis. 2014; 14:94.	Describes the genotypes of HBV and HDV in the Western Brazilian Amazon.⁽⁸8. Crispim MA, Fraiji NA, Campello SC, Schriefer NA, Stefani MM, Kiesslich D. Molecular epidemiology of hepatitis B and hepatitis delta viruses circulating in the Western Amazon region, North Brazil. BMC Infect Dis. 2014; 14:94.⁾	Cross-sectional study (descriptive)	VI
Mendes-Correa MC, Gomes-Gouvêa MS, Alvarado-Mora MV, Da Silva MH, Lázari C, Cavalcanti NCS, et al. Hepatitis delta in HIV/HBV co-infected patients in Brazil: is it important? Int J Infect Dis. 2011; 15(12):e828-32.	Assesses the prevalence of HDV among patients co-infected with human immunodeficiency virus (HIV) and HBV in São Paulo southeastern Brazil.⁽³³33. Mendes-Correa MC, Gomes-Gouvêa MS, Alvarado-Mora MV, Da Silva MH, Lázari C, Cavalcanti NC, et al. Hepatitis delta in HIV/HBV co-infected patients in Brazil: is it important? Int J Infect Dis. 2011; 15(12):e828-32.⁾	Cross-sectional study (descriptive)	VI
Gomes-Gouvea MS, Soares MCP, Bensabath G, de Carvalho-Mello IMVG, Brito EMF, Souza OSC, et al. Hepatitis B virus and hepatitis delta virus genotypes in outbreaks of fulminant hepatitis (Labrea black fever) in the western Brazilian Amazon region. J Gen Virol. 2009; 90(11):2638-43.	Describes the genotypes of HBV and HDV that circulate among the cases of fulminant hepatitis in the Brazilian Amazon Basin.⁽³⁴34. Gomes-Gouvea MS, Soares MC, Bensabath G, de Carvalho-Mello IM, Brito EM, Souza OS, et al. Hepatitis B virus and hepatitis delta virus genotypes in outbreaks of fulminant hepatitis (Labrea black fever) in the western Brazilian Amazon region. J Gen Virol. 2009; 90(11):2638-43.⁾	Cross-sectional study (descriptive)	VI
Nunes HM, Monteiro MRCC, Soares MCP. Prevalência dos marcadores sorológicos dos vírus das hepatites B e D na área indígena Apyterewa, do grupo Parakanã, Pará, Brasil. Cad Saúde Pública. 2007; 23(11):2756-66.	Studies the prevalence of HBV and HDV among the indigenous ethnicity Parakanã and assesses the impact of vaccination against hepatitis B starting in 1995 in the Apyterewa village in the state of Pará, Brazil.⁽³⁵35. Nunes HM, Monteiro MR, Soares M. Prevalência dos marcadores sorológicos dos vírus das hepatites B e D na área indígena Apyterewa, do grupo Parakanã, Pará, Brasil. Cad Saúde Pública. 2007; 23(11):2756-66.⁾	Cross-sectional study (descriptive)	VI
Viana S, Paraná R, Moreira RC, Compri AP, Macedo V. High prevalence of hepatitis b virus and hepatitis d virus in the western brazilian amazon. Am J Trop Med Hyg. 2005; 73(4):808-14.	Studies the prevalence of markers for hepatitis caused by HBV and HDV in the Western Brazilian Amazon.⁽³⁶36. Viana S, Paraná R, Moreira RC, Compri AP, Macedo V. High prevalence of hepatitis b virus and hepatitis d virus in the western brazilian amazon. Am J Trop Med Hyg. 2005; 73(4):808-14.⁾	Cross-sectional study (descriptive)	VI
Arboleda M, Castilho MC, Fonseca JF, Albuquerque BC, Saboia RC, Yoshida CFT. Epidemiological aspects of hepatitis B and D virus infection in the northern region of Amazonas, Brazil. Trans R Soc Trop Med Hyg. 1995; 89(5):481-3.	Identifies epidemiological patterns and risk factors for HBV and HDV infections in Barcelos, at the Rio Negro basin, Amazon region.⁽³⁷37. Arboleda M, Castilho MC, Fonseca JF, Albuquerque BC, Saboia RC, Yoshida CF. Epidemiological aspects of hepatitis B and D virus infection in the northern region of Amazonas, Brazil. Trans R Soc Trop Med Hyg. 1995; 89(5):481-3.⁾	Cross-sectional study (descriptive)	VI
Soares MC, Menezes RC, Martins SJ, Bensabath G. Epidemiologia dos vírus das hepatites B, C e D na tribo indígena parakanã, Amazônia Oriental Brasileira. Bol Oficina Sanit Panam. 1994; 124-35.	Studies the prevalence of infection with the hepatitis B, C and D viruses and describes its transmission among the indigenous ethnicity Parakanã in the state of Pará, Brazil.⁽³⁸38. Soares MC, Menezes RC, Martins SJ, Bensabath G. Epidemiologia dos vírus das hepatites B, C e D na tribo indígena parakanã, Amazônia Oriental Brasileira. Bol Oficina Sanit Panam. 1994; 117(2):124-35.⁾	Cross-sectional study (descriptive)	VI
Dantas LC, Genzini T, Miranda MP, Santos RG, Siqueira NG, Weirich J, et al. Liver transplantation in a patient with hepatitis B, C and D coinfection associated with hepatocellular carcinoma: a management strategy for a rare condition. Case report. Sao Paulo Med J. 2015; 133(6):525-30.	Presents a case report of a patient with hepatitis B, C and D subjected to antiviral treatment and liver transplantation.⁽³⁹39. Dantas LC, Genzini T, Miranda MP, Santos RG, Siqueira NG, Weirich J, et al. Liver transplantation in a patient with hepatitis B, C and D coinfection associated with hepatocellular carcinoma: a management strategy for a rare condition. Case report. Sao Paulo Med J. 2015; 133(6):525-30.⁾	Case report	VI
Fonseca JC. Hepatite D. Rev Soc Bras Med Trop. 2002; 35(2):181-90.	Presents a literature review on viral hepatitis of type D, showing aspects of the epidemiology, pathogenesis, diagnosis and treatment.⁽⁴⁰40. Fonseca JC. Hepatite D. Rev Soc Bras Med Trop. 2002; 35(2):181-90.⁾	Literature review	VI
Ribeiro LC, Souto FJD. Hepatite Delta no Estado de Mato Grosso: apresentação de cinco casos. Rev Soc Bras Med Trop. 2000; 33(6):599-602.	Presents a report of five cases of severe hepatitis Delta in the state of Mato Grosso, Brazil.⁽⁴¹41. Ribeiro LC, Souto FJD. Hepatite Delta no Estado de Mato Grosso: apresentação de cinco casos. Rev Soc Bras Med Trop. 2000; 33(6):599-602.⁾	Case report	VI
Oliveira MS, Silva RPM, Valle SCN, Figueiredo EN, Fram D. Chronic hepatitis B and D: prognosis according to Child-Pugh score. Rev Bras Enferm. 2017; 70(5):1048-53.	Compares patients with chronic hepatitis B to patients superinfected by the D virus according to the Child-Pugh score.⁽⁹9. Oliveira MS, Silva RP, Valle SD, Figueiredo EN, Fram D. Chronic hepatitis B and D: prognosis according to Child-Pugh score. Rev Bras Enferm. 2017; 70(5):1048-53.⁾	Cross-sectional study (descriptive)	VI
Paula V, Arruda M, Vitral C, Gaspar A. Seroprevalence of viral hepatitis in riverine communities from the Western Region of the Brazilian Amazon Basin. Mem Inst Oswaldo Cruz. 2001; 96(8):1123-8.	Investigates the presence of infection by hepatitis viruses A, B, C, D and E in communities living along the rivers Purus and Acre in the states of Acre and Amazonas, Amazon basin.⁽⁴²42. Paula V, Arruda M, Vitral C, Gaspar A. Seroprevalence of viral hepatitis in riverine communities from the Western Region of the Brazilian Amazon Basin. Mem Inst Oswaldo Cruz. 2001; 96(8):1123-8.⁾	Prevalence study (descriptive)	VI
Chachá SGF, Gomes-Gouvêa MS, Malta FM, Ferreira S da C, Villanova MG, Souza FF, et al. Distribution of HBV subgenotypes in Ribeirão Preto, Southeastern Brazil: a region with history of intense Italian immigration. Braz J Infect Dis. 2017; 21(4):424-32.	Determines the genotypes and subgenus of HBV circulating in southeastern Brazil and compares the genetic sequences found to HBV sequences previously described in the world.⁽⁴³43. Chachá SG, Gomes-Gouvêa MS, Malta F de M, Ferreira SC, Villanova MG, Souza FF, et al. Distribution of HBV subgenotypes in Ribeirão Preto, Southeastern Brazil: a region with history of intense Italian immigration. Braz J Infect Dis. 2017; 21(4):424-32.⁾	Case-control	IV
Braga WSM, de Oliveira CMC, de Araújo JR, Castilho MC, Rocha JM, Gimaque JB de L, et al. Chronic HDV/HBV co-infection: Predictors of disease stage – a case series of HDV-3 patients. J Hepatol. 2014; 61(6):1205-11.	Describes predictors of patients with chronic hepatitis B co-infected by HDV.⁽⁴⁴44. Braga WS, de Oliveira CM, de Araújo JR, Castilho MC, Rocha JM, Gimaque JB, et al. Chronic HDV/HBV co-infection: Predictors of disease stage - a case series of HDV-3 patients. J Hepatol. 2014; 61(6):1205-11.⁾	Cross-sectional study (descriptive)	VI
Botelho-Souza LF, dos Santos A de O, Borzacov LM, Honda ER, Villalobos-Salcedo JM, Vieira DS. Development of a reverse transcription quantitative real-time PCR-based system for rapid detection and quantitation of hepatitis delta virus in the western Amazon region of Brazil. J Virol Methods. 2014; 197:19-24.	develops a to detect and quantify the abundance of HDV particles in serum samples, based on quantitative reverse PCR (RT-qPCR).⁽⁴⁵45. Botelho-Souza LF, dos Santos AO, Borzacov LM, Honda ER, Villalobos-Salcedo JM, Vieira DS. Development of a reverse transcription quantitative real-time PCR-based system for rapid detection and quantitation of hepatitis delta virus in the western Amazon region of Brazil. J Virol Methods. 2014; 197:19-24.⁾	Clinical trial	III
Barros LMF, Gomes-Gouvêa MS, Pinho JRR, Alvarado-Mora MV, Dos Santos A, Mendes-Corrêa MCJ, et al. Hepatitis Delta virus genotype 8 infection in Northeast Brazil: Inheritance from African slaves? Virus Res. 2011; 160(1-2):333-9.	Assesses the seroprevalence of HDV among chronic carriers of HBsAg in the state of Maranhão, northeast Brazil.⁽⁴⁶46. Barros LM, Gomes-Gouvêa MS, Pinho JR, Alvarado-Mora MV, Dos Santos A, Mendes-Corrêa MC, et al. Hepatitis Delta virus genotype 8 infection in Northeast Brazil: Inheritance from African slaves? Virus Res. 2011; 160(1-2):333-9.⁾	Cross-sectional study (descriptive)	VI
Gomes-Gouvêa MS, Soares MCP, de Carvalho Mello IMVG, Brito EMF, Moia LJMP, Bensabath G, et al. Hepatitis D and B virus genotypes in chronically infected patients from the Eastern Amazon Basin. Acta Trop. 2008; 106(3):149-55.	Describes the genotypes of HBV and HDV housed in chronically infected patients in the Amazon Basin, Brazil.⁽⁴⁷47. Gomes-Gouvêa MS, Pereira Soares Mdo C, Guedes de Carvalho Mello IM, Brito EM, Pereira Moia Lde J, Bensabath G, et al. Hepatitis D and B virus genotypes in chronically infected patients from the Eastern Amazon Basin. Acta Trop. 2008; 106(3):149-55.⁾	Cross-sectional study (descriptive)	VI
Fonseca JC. Hepatite fulminante na Amazônia brasileira. Rev Soc Bras Med Trop. 2004; 37(Suppl 2):93-5.	The author makes a review and update on the results of research involving hepatitis of Lábrea hepatitis and other percussion caps of brazilian Western Amazonia, with emphasis on epidemiological, clinical and histopathologic features and viral etiology, such as hepatitis viruses B and D⁽⁴⁸48. Fonseca JC. Hepatite fulminante na Amazônia brasileira. Rev Soc Bras Med Trop. 2004; 37(Suppl 2):93-5.⁾	Literature review	VI
Fonseca JC, Simonetti SRR, Schatzmayr HG, Castejón MJ, Cesário ALO, Simonetti JP. Prevalence of infection with hepatitis delta virus (HDV) among carriers of hepatitis B surface antigen in Amazonas State, Brazil. Trans R Soc Trop Med Hyg. 1988; 82(3):469-71.	Performs an enzyme immunoassay to investigate HDV infection among individuals HBsAg asymptomatic.⁽⁴⁹49. Fonseca JC, Simonetti SR, Schatzmayr HG, Castejón MJ, Cesário AL, Simonetti JP. Prevalence of infection with hepatitis delta virus (HDV) among carriers of hepatitis B surface antigen in Amazonas State, Brazil. Trans R Soc Trop Med Hyg. 1988; 82(3):469-71.⁾	Cross-sectional study (descriptive)	VI
Bensabath G. Hepatitis Delta virus infection and Labrea hepatitis: prevalence and role in fulminant hepatitis in the amazon basin. JAMA. 1987; 258(4):479.	Studies the epidemiology of HDV infection to confirm its role on causing fulminant Labrea hepatitis, District of Boca do Acre, Amazon Basin, Brazil.⁽¹⁴14. Bensabath G. Hepatitis Delta virus infection and Labrea hepatitis: prevalence and role in fulminant hepatitis in the Amazon Basin. JAMA. 1987; 258(4):479.⁾	Cross-sectional study (descriptive)	VI
Strauss E, Gayotto LCC, da Silva LC, Alves VAF, Carrilho F, Chamone DAF, et al. Unexpected low prevalence of delta antibodies in the east Amazon region and São Paulo: evidence for regional differences in the epidemiology of delta hepatitis virus within Brazil. Trans R Soc Trop Med Hyg. 1987; 81(1):73-4.	Investigates antibodies (anti-HD) for HDV among symptomatic and asymptomatic carriers of HBsAg in Eastern Amazon (states of Pará and Amapá) and São Paulo, Brazil.⁽⁵⁰50. Strauss E, Gayotto LC, da Silva LC, Alves VA, Carrilho F, Chamone DA, et al. Unexpected low prevalence of delta antibodies in the east Amazon region and São Paulo: evidence for regional differences in the epidemiology of delta hepatitis virus within Brazil. Trans R Soc Trop Med Hyg. 198781(1):73-4.⁾	Cross-sectional study (descriptive)	VI