Many believe that, the causative organisms may be present in the soil in the form of grains. After they are moistened by rain, they form conidia or other forms capable to infect the host. This infecting agent is then implanted into the host tissue through a breach in the skin produced by local trauma caused by sharp objects such as thorn pricks, stone or splinters.
In areas where mycetoma is frequent, the habit of going barefooted is common and thorns are plentiful. As a result, natural infection is expected to be more frequent than it actually is, if this hypothesis of route of infection is true. Many workers in the field believe that, there is an intermediate host for the infection to develop but it is not known.
It is interesting to note, that it was not possible to isolate Madurella mycetomatis, the main causative agent of human eumycetoma in Sudan from different soils and thorn tree samples from different endemic areas in the country. However, PCR-mediated detection followed by restriction fragment length polymorphism (RFLP) analysis for the identification of Madurella mycetomatis DNA from the environmental samples was done and it was positive in 23% of soil and in 5% of the thorn samples. These observations support the hypothesis that eumycetoma is primarily environmentally acquired and suggest that Madurella mycetomatis needs special conditions for growth, as direct isolation from the environment seems to be impossible.
The Central Sudan is endemic area for eumycetoma due to Madurella mycetomatis. The majority of villagers in that area are farmers and live on animal husbandry. They have many cattle, goats, sheep, dogs, chickens and donkeys and they are kept in cages surrounded by walls made of mud or dry thorny bushes. The floors of the cages are covered with dry animals dung, thorns and trash. The villagers’ homes are in close proximity with these cages. As the frequency of Madurellamycetomatis on thorns is low as documented previously, and the common habit of going barefooted, contaminated animal dung and its role as an adjuvant may has important roles in contracting mycetoma.
The disease can occur naturally in a number of animals including goats, horses, donkeys, dogs, and cats. However, the disease is not contagious from animal to human or from one person to another and there is no report on hospital cross- infection.