Sporadic cases of acute hepatitis E among ten native Nigerian adults were reported in Port-Harcourt (Nigeria). Hepatitis E virus (HEV) was detected in serum and/or faecal samples of seven patients by RT–PCR of the open reading frame (ORF)-1 polymerase region and the 3′-end of ORF2. Restriction analysis widely used to distinguish genotypes I and III showed that all Nigerian strains have a pattern similar to the Mexican strain (I, nt 286; I, nt 397; no I restriction site) but displayed a I restriction site at nt 213 as do most African HEV strains sequenced so far. Sequence analysis performed from internal ORF1 and ORF2 PCR products displayed strong homogeneity between the HEV isolates, determining a regional cluster. Phylogenetic analysis of nucleotide sequences revealed that these strains were more related to the Mexican prototype genotype III (87% homology in ORF1, 80% homology in ORF2) than to either the African strain genotype I (74% homology in ORF1, 77% homology in ORF2) or the USA strain genotype II (75% homology in ORF1, 77% homology in ORF2). Genetic divergence up to 15% in ORF2 with the Mexican genotype clearly defined a new subgenotype within genotype III. At the amino acid level, Nigerian strains showed more homology with genotype III (96%) than with genotype I (92%). This study clearly determined the co-existence of genotypes I and III in Africa. These Nigerian HEV strains belonging to genotype III, but sharing some properties with genotype I, could be one of the missing links between African and Latin American HEV and could help us to determine the phylogenetic evolution of HEV from the ancestral virus.


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  1. Aye, T. T., Uchida, T., Ma, X., Iida, F., Shikata, T., Zhuang, H. & Win, K. M. (1992). Complete nucleotide sequence of a hepatitis E virus isolated from the Xinjiang epidemic (1986–1988) of China. Nucleic Acids Research 20, 3512.[CrossRef] [Google Scholar]
  2. Bi, S. L., Purdy, M. A., McCaustland, K. A., Margolis, H. S. & Bradley, D. W. (1993). The sequence of hepatitis E virus isolated directly from a single source during an outbreak in China. Virus Research 28, 233-247.[CrossRef] [Google Scholar]
  3. Chatterjee, R., Tsarev, S. A., Pillot, J., Coursaget, P., Emerson, S. U. & Purcell, R. H. (1997). African strains of hepatitis E virus that are distinct from Asian strains. Journal of Medical Virology 53, 178-182. [Google Scholar]
  4. Dawson, G. J., Chau, K. H., Cabal, C. M., Yarbough, P. O., Reyes, G. R. & Mushawar, I. K. (1992). Solid-phase enzyme-linked immunosorbent assay for hepatitis E virus IgG and IgM antibodies utilizing recombinant antigens and synthetic peptides. Journal of Virological Methods 38, 175-186.[CrossRef] [Google Scholar]
  5. Donati, M. C., Fagan, E. A. & Harrison, T. J. (1997). Sequence analysis of full length HEV clones directly derived from human liver in fulminant hepatitis E. In Viral Hepatitis and Liver Disease, pp. 313-316. Edited by M. Rizetto, R. H. Purcell, J. L. Gerin & G. Verme. Torino: Edizoni Minerva Medica.
  6. Drabick, J. J., Gambel, J. M., Gouvea, V. S., Caudill, J. D., Sun, W., Hoke, C. H.Jr & Innis, B. (1997). A cluster of acute hepatitis E infection in United Nations Bangladeshi peacekeepers in Haiti. American Journal of Tropical Medicine and Hygiene 57, 449-454. [Google Scholar]
  7. Erker, J. C., Desai, S. M., Schlauder, G. G., Dawson, G. J. & Mushahwar, I. K. (1999). A hepatitis E virus variant from the United States: molecular characterization and transmission in cynomolgus macaques. Journal of General Virology 80, 681-690. [Google Scholar]
  8. Gouvea, V., Hoke, C. H. & Innis, B. (1998). Genotyping of hepatitis E virus in clinical specimens by restriction endonuclease analysis. Journal of Virological Methods 70, 71-78.[CrossRef] [Google Scholar]
  9. Huang, C. C., N’Guyen, D., Fernandez, J., Yun, K. Y., Fry, K. E., Bradley, D. W., Tam, A. W. & Reyes, G. R. (1992). Molecular cloning and sequencing of the Mexico isolate of hepatitis E virus (HEV). Virology 191, 550-558.[CrossRef] [Google Scholar]
  10. Huang, R., Nakazono, N., Ishii, K., Kawamata, O., Kawaguchi, R. & Tsukada, Y. (1995). Existing variations on the gene structure of hepatitis E virus strains from some regions of China. Journal of Medical Virology 47, 303-308.[CrossRef] [Google Scholar]
  11. Krawczynski, K., Bradley, D., Ajdukiewicz, A., Alter, M., Carreda, F., Dilawari, J., Hiady, G., Innis, B., Qkane, M., Nasidi, A., Redeker, A., Stetler, H., Toukan, A. & Yoffee, B. (1991). Virus-associated antigen and antibody of epidemic non-A, non-B hepatitis: serology of outbreaks and sporadic cases. In Viral Hepatitis C, D & E, pp. 229-236. Edited by T. Shikata, R. H. Purcell & T. Uchida. Amsterdam: Elsevier.
  12. Meng, X. J., Halbur, P. G., Shapiro, M., Govindarajan, S., Bruna, J. D., Mushahwar, I. K., Purcell, R. H. & Emerson, S. U. (1998). Genetic and experimental evidence for cross-species infection by swine hepatitis E virus. Journal of Virology 72, 9714-9721. [Google Scholar]
  13. Meng, J., Cong, M., Dai, X., Pillot, J., Purdy, M. A., Fields, H. A. & Khudyakov, Y. E. (1999). Primary structure of open reading frame 2 and 3 of the hepatitis E virus isolated from Morocco. Journal of Medical Virology 57, 126-133.[CrossRef] [Google Scholar]
  14. Schlauder, G. G., Desai, S. M., Zanetti, A. R., Tassopoulos, N. C. & Mushahwar, I. K. (1999). Novel hepatitis E virus isolates from Europe: evidence for additional genotypes of HEV. Journal of Medical Virology 57, 243-251.[CrossRef] [Google Scholar]
  15. Tam, A. W., Smith, M. M., Guerra, M. E., Huang, C. C., Bradley, D. W., Fry, E. & Reyes, G. R. (1991). Hepatitis E virus (HEV): molecular cloning and sequencing of the full-length viral genome. Virology 185, 120-131.[CrossRef] [Google Scholar]
  16. Touze, A., Enogat, N., Buisson, Y. & Coursaget, P. (1999). Baculovirus expression of chimeric hepatitis B core particles with hepatitis E epitopes, and their use in a hepatitis E immunoassay. Journal of Clinical Microbiology 37, 438-441. [Google Scholar]
  17. Tsarev, S. A., Emerson, S. U., Reyes, G. R., Tsareva, T. S., Legters, L. J., Malik, I. A., Iqbal, M. & Purcell, R. H. (1992). Characterization of a prototype strain of hepatitis E virus. Proceedings of the National Academy of Sciences, USA 89, 559-563.[CrossRef] [Google Scholar]
  18. Tsarev, S. A., Binn, L. N., Gomatos, P. J., Arthur, R. R., Monier, M. K., van Cuyck-Gandré, H., Longer, C. F. & Innis, B. (1999). Phylogenetic analysis of hepatitis E virus isolates from Egypt. Journal of Medical Virology 57, 68-74.[CrossRef] [Google Scholar]
  19. van Cuyck-Gandré, H., Zhang, H. Y., Clements, N. J., Cohen, S. G., Caudill, J. D., Coursaget, P., Buisson, Y., Warren, R. l. & Longer, C. F. (1996). Partial sequence of HEV isolates from North Africa and Pakistan: comparison with known HEV sequences. In Enterically-transmitted Hepatitis Viruses, pp. 301-310. Edited by Y. Buisson, P. Coursaget & M. Kane. Joue-les-Tours, France: La Simarre.
  20. van Cuyck-Gandré, H., Zhang, H. Y., Tsarev, S. A., Clements, N. J., Cohen, S. J., Caudill, J. D., Buisson, Y., Coursaget, P., Warren, R. L. & Longer, C. F. (1997). Characterization of hepatitis E virus (HEV) from Algeria and Chad by partial genome sequence. Journal of Medical Virology 53, 340-347.[CrossRef] [Google Scholar]
  21. Wang, Y., Ling, R., Erker, J. C., Zhang, H., Li, H., Desai, S., Mushahwar, I. K. & Harrison, T. J. (1999). A divergent genotype of hepatitis E virus in Chinese patients with acute hepatitis. Journal of General Virology 80, 169-177. [Google Scholar]
  22. Yarbough, P. O., Tam, A. W., Gabor, K., Garza, E., Moeckli, R. A., Palings, I., Simonsen, C. & Reyes, G. R. (1994). Assay development of diagnostic tests for hepatitis E. In Viral Hepatitis & Liver Disease, pp. 367-370. Edited by K. Nishioka, H. Suzuki, S. Mishiro & T. Oda. Tokyo, Japan: Springer-Verlag.
  23. Yi, S., Purcell, R. H. & Emerson, S. U. (1994). A new Chinese isolate of hepatitis E virus: comparison with strains recovered from different geographical regions. Virus Genes 9, 23-32.[CrossRef] [Google Scholar]
  24. Zharkikh, A. & Li, W. H. (1992). Statistical properties of bootstrap estimation of phylogenetic variability from nucleotide sequences. I. Four taxa with a molecular clock. Molecular Biological Evolution 9, 1119-1147. [Google Scholar]

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