O. Adekanmbi1, K. Osinusi2

  1. Department of Medicine, University College Hospital, Ibadan.
  2. Department of Paediatrics, University College Hospital, Ibadan.

An emerging infectious disease is one that is found in a human population for the first time or that has recently expanded into a new geographical location.1 It also refers to a known pathogen newly appearing in resistant form.1 The majority of these infections are zoonotic in nature and tend to emerge following the complex interactions between pathogens, their host (human or animal) and the environment.2 All these actors largely exist in equilibrium in nature until this delicate balance is upset leading to the emergence of new infectious diseases from time to time.

The pathogen factors responsible for the emergence of new infections are modulated by changes at the genetic level and are often an evolutionary response to perceived existential threat or to aid their survival. An example is mutations that enable cross species transfer from an animal to human host. Similarly, there are a myriad of host variables such as genetic features that reduce or increase susceptibility in an individual host or an entire host population.3 There are several interactions between (human) hosts and the environment that contribute to the emergence of new infections. Activities such as deforestation, large-scale construction and industrialized farming which disturb the natural habitat of animals can be a catalyst for the emergence of new infections. These activities displace animals which serve as natural reservoirs for potential emerging pathogens, forcing them into areas inhabited by humans to forage for food and find new habitations. Likewise, the process of carrying out the above-described activities in the environment leads humans into these largely uncharted spaces. These human activities are often for economic development and to accommodate growing populations; they put a strain on natural resources leading to shortages in essential resources such as land, food, and water. Ultimately, both humans and animals are jostling for scarce resources resulting in on-going harmful exposures for humans. Another very important aspect of human activity that contributes significantly to the emergence of new infections is international travel for obvious reasons.

Since May 2022, the has been a global resurgence of mpox. Historically endemic in central and western African countries, it has since been reported in several non-endemic countries with majority of the affected persons having no antecedent travel to endemic areas thus suggesting the establishment of local transmission. It also highlights the important role that fast and efficient travel plays in the emergence of an infectious disease in a new location. According to the World Health Organization (WHO), mpox cases have been reported from 117 countries across all six WHOregions with a tally of 94,707 confirmed cases and 181 deaths as of 29 February 2024.4 Notably, one country, Cambodia, reported her very first case in February 2024.4 Outside mpox endemic areas, the main group of individuals affected by the disease are men who have sex with men (MSM). An observational analysis of patients diagnosed with mpox at a sexual health clinic in the UK by Girometti et al found that all of them identified as MSM, 94% of them had anogenital mpox lesions and a quarter of them had a concomitant sexually transmitted infections (STI).5 Taken together, these suggest sexual transmission of mpox and that high-risk sexual practices might be a factor in transmission in the MSM population. These might be the origins of stigma associated with mpox as is also seen with HIV and other STIs. The WHOchanged the nomenclature of the disease from monkey pox to mpox in November 2022 in attempt to address stigma associated with the disease.

Nigeria is experiencing an mpox outbreak which began in 2017. Between June and December 2022, Nigeria contributed more cases to the global case count of patients with mpox than any other African country.4 Also of note, while Africa was responsible for only 3% of the cases of mpox in the global outbreak, 12%of the deaths associated with the disease were fromthe region.4 This high mortality rate is not uniformacross endemic African countries as the Congo Basin clade (found in Central Africa) tends to be more virulent than the West African clade (found in West Africa). The disproportionately high mortality in African countries is concerning and should motivate increased readiness and response to emerging infectious diseases in Africa and similar settings. In this issue, Bakare et al explore the level of awareness, knowledge, and risk perception in communities across three states in Nigeria. They found significant knowledge gaps and very low levels of awareness in these communities.