A tale of two clades: monkeypox viruses

Abstract

Human monkeypox was first recognized outside Africa in 2003 during an outbreak in the USA that was traced to imported monkeypox virus (MPXV)-infected West African rodents. Unlike the smallpox-like disease described in the Democratic Republic of the Congo (DRC; a Congo Basin country), disease in the USA appeared milder. Here, analyses compared clinical, laboratory and epidemiological features of confirmed human monkeypox case-patients, using data from outbreaks in the USA and the Congo Basin, and the results suggested that human disease pathogenicity was associated with the viral strain. Genomic sequencing of USA, Western and Central African MPXV isolates confirmed the existence of two MPXV clades. A comparison of open reading frames between MPXV clades permitted prediction of viral proteins that could cause the observed differences in human pathogenicity between these two clades. Understanding the molecular pathogenesis and clinical and epidemiological properties of MPXV can improve monkeypox prevention and control.

Ecology and Geography of Human Monkeypox Case Occurrences Across Africa

“…that is similar to other known orthopoxviruses in Uganda (Goldberg et al, 2008). A geographic break in the potential distribution of human monkeypox, located along the border of eastern Nigeria and western Cameroon in an area characterized by a chain of mountain ranges and volcanoes known as the Cameroon Range, was noted in both studies and may correspond to the distributional gap between the two major monkeypox clades (Chen et al, 2005;Likos et al, 2005).…”

“…In the Congo Basin, monkeypox is associated with higher case numbers and increased morbidity, mortality, viremia, and transmission via human-to-human contact when compared with cases in West Africa (Chen et al, 2005;Likos et al, 2005). Initial molecular genetic studies and whole-genome analyses of monkeypox isolates indicate the presence of two distinct strains (Mackett and Archard, 1979;Esposito and Knight, 1985;Likos et al, 2005).…”

“…In the Congo Basin, monkeypox is associated with higher case numbers and increased morbidity, mortality, viremia, and transmission via human-to-human contact when compared with cases in West Africa (Chen et al, 2005;Likos et al, 2005). Initial molecular genetic studies and whole-genome analyses of monkeypox isolates indicate the presence of two distinct strains (Mackett and Archard, 1979;Esposito and Knight, 1985;Likos et al, 2005). Isolates from outbreaks in Cameroon, Republic of the Congo, Gabon, and the DRC comprise the Congo Basin clade, whereas isolates from Nigeria, Liberia, and those imported from Ghana into the United States constitute the West African clade (Reed et al, 2004;Likos et al, 2005;Sale et al, 2006).…”

The Vaccinia Virus Complement Control Protein Modulates Adaptive Immune Responses during Infection

“…Both VARV and MPXV express orthologs of VCP that have been shown to regulate complement activation in vitro (30-32, 46, 48). The MPXV homolog of VCP (known as MoPICE) is thought to contribute to virulence because it is expressed by the more virulent Central African strain of this virus but is not found in the less pathogenic West African strain (6,29). Additionally, complement-deficient mice succumb to infection with ECTV (40), demonstrating the importance of complement in protection against pathogenic poxvirus infection.…”

Clinical signs, diagnosis, and case reports of Vaccinia virus infections

“…6 However, zoonoses caused by poxviruses have occurred in regions far from their endemic areas, such as the outbreak of Monkeypox (MPXV) in central North-American states during May and June 2003, which was the fi rst identifi ed out of Africa. [7][8][9] In Brazil, since 1960, innumerous outbreaks related to Vaccinia virus have been documented by several research groups in different regions. Based on molecular studies, some 10 The number of human cases and new viruses isolated should increase because new epidemic foci have been reported in different areas.…”