In an article titled, "Monkeypox can be airborne, too" the CDC's leading monkeypox expert Andrea McCollum said this was not a disease that transmitted over several meters. (Not true, see my thread for studies showing this).
Countries can have different housing styles. New houses in the US tend to be energy efficient. Which tends to mean, not very good ventilation.
Homes in Africa differ too, depending on the region.
Bad ventilation means aerosols build in concentration.
Aerosols concentrating
means a greater amount of inhalation, so lesser transmissible diseases like WT CoVid and the current MPX in the west, have a greater chance of infection.