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2nd Blog
As a summary of the previous blog, we decided to arrive at 4 main types of microorganism (Fungal and protozoa). They are the dermatophytes (Trichophytom mentagrophytes, Epidermophyton floccosum, Trichophyton rubrum ), Flagellate (Giardia lamblia), Amoeba (Entaemoeba Histolytica) & plasmodium species (P. Vivax, P.ovale, P.falciparum & P.malariae). Below are the rationale why the following microbes are selected over the others.

Giardia Lamblia
Basically, this protozoa is mainly transmitted via water. It is a waterborne microbes that could lead to intestinal disease such as diarrhea. It is basically transmitted through ingestion of cyst in fecally contaminated water or food. In a jungle area setting where lakes and rivers are a common sight, these could trigger off outbreaks if soldier man is not careful. These sources of water from the lakes and river are often used by soldier when their water supplies run out. Water from the lakes or river may appear clear looking but may harbour organism such as Giardia Lamblia. As such the incidence rate of outbreak associated with this microbe is fairly high.

Entamoeba Histolytica

Simiarly to Giardia Lamblia, the same mode of transmission applies to Entamoeba Histolytica. As such, the rationale applies here and Entamoeba Histolytica is also commonly found in contaminated water.


Malaria caused by Plasmodium spp

Malaria is a common disease caused by a microscopic parasite that is passed along from one infected person to another by mosquitoes. Malaria occurs in more than 100 countries worldwide, infecting 300 million to 500 million people, and causing about 1 million deaths, each year. The reason we include it is due to the area of outbreak with malaria. It is said that the malaria zone is very broad and widely distributed covering areas from Africa to central asian to even Southern asia(1). Since Brunei is part of southern asia zone, it is regarded as a highly important prozotoa species.

Dermatophytes

This group of fungi thrives in conditions when 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. As such, tropical climate of Brunei jungle which is often hot, high humidity level will encourage the spread of infection by the dermatophytes, jeopardizing the soldier that is often sweaty and oily due to excessive training.

References :

1)InteliHealth
http://www.intellihealth.com

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

Protozoal infections

In a setting such as Brunei jungle where sanitation system are often poor & many unknown sources of water from lakes and river, contaminated water sources are often the source that eventually lead to outbreaks if there is any. As such, all water-borne protozoa are emphasized and described in greater details.

1.6 Entamoeba Histolytica (Amoebiasis)

Brief overview

Entamoeba histolytica is a common parasite in the large intestine of humans. It is often present in 3 stages: the active ameba, the inactive cyst or the intermediate precyst. Entamoeba histolytica can cause amoebiasis which is usually contracted by ingesting water or food contaminated by amoebic cysts. This is usually a waterborne disease. It also can be transmitted by direct contact with dirty hands .

Mode of transmission
• Ingestion of cyst transmitted by fecal oral route in contaminated food and water.

Associated symptoms :
Symptoms are usually gastrointestinal such as diarrhea, vomiting, abdominal pain or discomfort and fever. Dysentry (bloody stool) is often observed in people infected with entamoeba histolytica. Amebic liver abscess with symptoms such as right upper quandrant pain, weight loss, fever, tender & enlarged liver. Symptoms take from a few days to a few weeks to develop and manifest themselves (Usually 2- 4 wks). Most infected patients are asymptomatic. Most infection occur in the digestive tract but other tissues may be invaded. Complications include ulcerative and abscess pain.

Treatment / Prevention

Infection with Entamoeba histolytica occurs in both the intestine and/or the liver. Asymptomatic amebiasis can be treated with iodoquinol, furamide or paromomycin. Paromomycin is the most effective drug for treating intestinal infection. Metronidazole is the drug of choice to destroy the amebae that invaded tissues. Both types of drug must be given to treat infection, with metronidazole usually being given first followed by paromomycin.

Prevention or control measures consist of improving environmental and food sanitation as cysts are usually ingested through contaminated water. In the tropics, contaminated food and vegetables are also important cyst sources. As such, avoid contamination of food and water and promote good personal hygiene such as hand washing regularly. Use of purification tablets to purify water supply especially in tropics zone is also essential and lastly, always cook vegetable or any food fully before consumption.

1.7 Sporozoa- Plasomodium sp (Malaria parasite)

There are four species of plasmodia namely plasmodium vivax, plasmodium ovale, plasmodium malariae and plasmodium flaciparum. Mode of transmission to humans is by the bloodsucking bite of female anopheles mosquito of various species. Malaria today is generally limited to the tropic and subtropics area. The life cycle of malaria parasite include sporozites, merozoites, erythrocytic development and sporogony.

Clinical features:
Most common associated clinical features include high fever, nausea, vomiting & headaches, anaemia (pale-looking like face due to destruction of red blood cells).

Treatment
Chloroquine (Aralen) is the drug of choice for treatment of all susceptible forms of malaria during the acute attack. In the case of resistant to chloroquine, mefloquine is now the chemoprophylatic drug of choice to be administered to patient. Primaquine eliminates the exoerythrocytic forms in the liver. Malaria coma from chloroquine-resistant falciparum malaria should be treated with parental quinine or quinidine plus intravenous doxycycline or clindamycin. Oral therapy should replace parental treatment as soon as possible.

Prevention / Control

Anti-malarial drug such as maloprim or primaquine can be given to man before they venture into any tropics area such as the jungle or forest. Personal protection against mosquitoes can be enhanced by clothing with love sleeves and trousers or even usage or repellents.

1.8 Flagellate – Giardia lamblia

Giardia lamblia is the only common pathogenic protozoan found in the duodenum and jejunum of humans. Similarly to entamoeba histolytica, mode of transmission is through the ingestion of cyst in fecally contaminated food and water or by direct fecal contamination. Cysts can survive in water for up to 3 months. In poor sanitiation areas such as jungle, outbreaks that are associated with giardia is not surprising since poor hygiene practices are commonly present in tropic area settings.

Clinical features :
Nonbloody, foul smelling diarrhea, nausea, anorexia, flatulence & abdominal cramps.

Treatment

Metronidazole will clear over 90% of G lamblia infections. Oral quinacrine hydrochloride (Atabrine) and furazolidone (Furoxone) are alternatives.

Prevention
It can be prevented by drinking boiled, filtered, iodine treated water in areas with poor sanitiation system or unreliable source of water.

1.9 Sporozoa – Toxoplasma

Brief Overview
Diseases caused by Toxoplasma gondii are known as toxoplasmosis. It is usually transmitted by ingestion of cysts in uncooked meat or food contaminated with cat feces. Since it is primarily transmitted through food sources, it was shortlisted since uncooked or not fully cooked food is very likely to present in an area without proper cooking tools or gases.

Treatment
Acute infection can be treated with a combination of pyrimethamine and sulfadiazine or trisulfapyrimidines. Alternative drugs include spiramycin, clindamycin, trimethoprim-sulfamethoxazole and various other sulfonamide drugs.

1.10 Helminths- Wuchereria bancrofti

Brief overview
Wuchereria bancrofti is a parasitic filarial worm that causes lymphatic filariasis, which is the inflammation and obstruction of lymphatic glands, sometimes resulting in elephantiasis if left untreated. It is suspected as the disease is found primarily in Africa, South America, and other tropical and sub-tropical countries.

Mode of transmission
The disease spreads from person to person by mosquito bites. When a mosquito bites a person who has lymphatic filariasis, microscopic worms circulating in the person's blood enter and infect the mosquito. People get lymphatic filariasis from the bite of the infected mosquito.

Associated symptoms :
Symptoms include swelling and impaired circulation. The lymphatic system becomes dysfunctional as it becomes hardened and clogged with fibrous tissue. Without the proper drainage of fluids, the affected tissue will expand and elephantiasis can occur as a result.

Treatment / Prevention
Either ivermectin, albendazole, or diethylcarbamazine is used to treat the infection. Unfortunately, much of the tissue damage may not be reversible. The medication is started at low doses to prevent reactions caused by large numbers of dying parasites.

*Summary
In summary, unknown sources of water either from lakes or river that could harbour parasites such as Giardia lamblia or Entamoeba Histolytica that may unknowingly causes disease in soldiers after drinking those contaminated water which may seem clear in color at one glance. Environment settings of jungle where there could be many mosquitoes could contribute to infection such as malaria by P. Vivax, P.Malariae, P.falciparum & P.ovale as well as lymphatic filariasis by Wuchereria bancrofti.

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

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.