Fungal infections

To reiterate that the following climate of Brunei jungle zone could promote host susceptibility to certain fungal infection that thrive best in those weather condition, we have managed to list out a series of causing fungal agents that could most probably resulted in outbreaks in army soldier.

1. Dermatophytes

Dermatophytes, comprises of about 40 related fungi belong to 3 genera namely microsporum, trichophyton and epidermophyton. They are commonly associated with skin infection (head, leg etc). Dermatophyte infections were commonly terms as ringworm or tinea due to the presence of raised circular lesions. The clinical forms are based on the site of involvement.

Dermatophytes are classified as geophilic, zoophilic or anthrophilic depending on whether their usual habitat is soil, animal or human. Some examples of anthrophilic species include Epidermophyton fluoccosum, Trichophyton mentagrophytes var interdigitale, T rubrum and T tonsurans. Most common geophilic.

Dermatophyte infections normally begin in the skin after trauma and contact. These group of fungi thrives in conditions there is moisture, warmth, specific skin chemistry, composition of sebum and perspiration, youth, heavy exposure and genetic predisposition. The incidence is higher in hot, humid climates and under crowded living conditions. Wearing shoes provide warmth and moisture, a predisposing setting for infection of the feet.

1.1 Athlete’s food or commonly known as Jungle Rot (Tinea Pedis or foot ringworm) caused by T rubrum, T mentagrophytes and E floccosum

Brief Description
• It is the most prevalent of all dermatophyoses. It usually occurs as a chronic infection of the toewebs. It mostly affects teens and adult males. Contributing factors include sweating, not drying the feet well after bathing or swimming, wearing tight socks and shoes and warm weather conditions. Location of lesions associated with athelete’s foot is normally at the interdigital spaces on feet of person wearing shoes. Symptoms of athelete’s foot include whitening of the skin between the toes, scaling of the feet, itchy rash on the feet or even blisters on the feet

1.2 Tinea corporis (ringworm) caused by T rubrum, E floccosum

Brief description
• The location of lesions is situated at the non-hairy, smooth skin of a person. It is characterized by a ring-like rash anywhere on the body or the face. Clinical features generally include circular patches with advancing red, vesiculated border and central scaling.

1.3 Tinea cruis (Jock itch or groin ringworm)

Brief Description
• When the infection occurs in the groin area, it is called tinea cruris. It is more prevalent in males, rarely in females. It present as dry, itchy lesion that often start on the scrotum and spread to the groin area. Symptoms of jock itch include red, ring-like patches in the groin area, itching in the groin area & pain in the groin area.

1.4 Tinea capitis ,Tinea Barbae & Tinea unguium

Brief Description
• Tinea capitis is dermatophytosis or ringworm of the scalp and hair and Tinea unguium is an infection of the toe nail, characterized by thickened or deformed nails. Symptoms of nail ringworm may include thickening of the ends of nail or yellow color to the nails.

Treatment / Prevention
Treatment ways include removal of infected and dead epithelial structures and application of a topical antifungal chemical or antibiotic. To prevent reinfection, area should be kept dry. Treatment for scalp ringworm (tinea capitis) include oral anti-fungal medication which is prescribed for 4-8 weeks. Griseofulvin can be given for treatment of tinea capitis. Frequent shampoos and miconazole cream or other topical antifungal agents may be effective if used for weeks. For tinea corporis or / & tinea pedis, itraconazole and terbinafine are the choice of drugs.

1.5 Candida sp (Yeast)
Several species of the yeast genus candida are capable of causing candidasis. They are members of the normal flora of the skin, mucous membranes and gastrointestinal tract. Candidasis is the most common systemic mycosis and the most common agents are C albicans, C tropicalis, C parapsilosis, C glabrata, C guilliermondii and C dubliniensis. Three types of candidiasis can develop and they are known as cutaneous and mucosal candidiasis, systemic candidiasis & chronic mucocutaneous candidiasis.

Cutaneous and Mucosal Candidiasis
Risks factors associated with this disease include trauma such as burns or maceration of the skin. Cutaneous candidiasis include invasion of the skin when the skin is weakened by burns, trauma or maceration. Intertriginous infection occurs in moist and warm parts of the body such as axillae, groin and intergluteal or inframammary folds. Infected areas may become red and moist and develop vesicles.

Treatment / Prevention
Thrush and other mucocutaneous forms of candidiasis are usually treated with tropical nystatin, ketoconazole or fluocnazole. Systemic candidiasis is treated with amphotericin B sometimes in conjuction with oral flucytosine, fluconazole or caspofungin. Clearing of cutaneous lesions is accelerated by elimating contributing factors such as excessive moisture or antibacterial drugs.

The most important preventive measure is to avoid disturbing the normal balance of microbial flora and intact host defenses.

1.6 Cryptococcus sp (Yeasts)

In Cryptococcus sp, the most clinically significant species is cryptococcus neoformans. It is characterized by a thick polysaccharide capsule. It occur worldwide in nature and is found in very large number in dry pigeon feces that could reside or hidden underneath the soil. Infections follow inhalation of the yeast cells which in nature are dry, minimally encapsulated and easily aerolized.

Transmission

It is widely occurring in nature and grows in soil containing pigeon droppings. In addition, it can be transmitted by inhaling airborne yeast cells. Direct contact of soil containing the crptococcus may cause one to get infected through the inhalation of the fungus into the body.

Prevention / Treatment

Since the predominant source of Cryptococcus neoformans comes from the birds, there are generally no specific means of prevention. Treatment against Cryptococcus sp can be achieved by combining the use of amphotericin B and flucytosine for meningitis.

1.7 Aspergillus sp

Aspergillus sp are often opportunistic pathogens that can cause disease or infection in humans. They are normally found in soil and transmitted via inhalation of airborne spores.
In an area setting like Brunei jungle, there may be direct or indirect contact between the ground soil and the soldier during training. Some clinically important species of Aspergillus include A.fumigatus, A.Flavus & A.niger

Clinical signs and symptoms :Associated clinical signs and symptoms may include fever, malaise, cough, wheezing, weight loss, chest pain and headache.

Treatment / Prevention

Treatment against Aspergillus sp can be carried out using amphotericin B to treat invasive aspergillosis. Beside that, fungal balls can be surgically removed and steroids can be consumed for allergic bronchopulmonary aspergillosis. Currently, there are no vaccine or prophylactic drug for to prevent Aspergillus infection

*Summary
In summary, fungal infection outbreak could happens in a clinical setting where climate are often hot and humidity levels are high such as tropical areas in Asian countries (Brunei). In addition, the harsh living conditions of NS soldier (Excessive perspiration seldom bathe, unhygienic practices) could further promote infection caused by fungi with specific examples such as dermatophytes. In addition, inevitable contacts with soil during training could further promote fungal infection with specific examples such as Aspergillus Sp and Cryptococcus neoformans


References
1. Geo. F. Brooks, Janet S. Butel, Stephen A. Morse. (2001). Medical
Microbiology. Singapore.McGraw-Hill.