Introduction
Tropical areas refer to the regions of the earth around the equator. Tropical countries have a warm climate as they receive more direct sunlight than the rest of the earth. This region accounts for 36 percent of the earth's land area and has only wet and dry seasons. Certain diseases are common within the tropics that cause serious infections to the people residing in these areas. Specific measures are taken to control them and prevent their occurrence.
What Are the Various Tropical Diseases?
Numerous diseases are unique to tropical regions. They include:
-
Tropical Ulcer - A painful bacterial ulcer that occurs in tropical climates.
-
Mycobacterial Ulcer - An ulcer caused by Mycobacterium ulcerans.
-
Fournier’s Gangrene - A highly infectious soft tissue infection affecting the scrotum.
-
Cancrum Oris - An infectious gangrene (death of the affected part) of the cheek and the mouth.
-
Pyomyositis - Infection of the skeletal muscles.
-
Spleen - In the tropics, the conditions affecting the spleen are splenomegaly (enlargement of the spleen), splenic abscess (spleen infection), and splenic trauma.
-
Tuberculosis - A bacterial disease affecting the breast and abdomen are common in tropical countries.
-
Amoebiasis - A disease that occurs due to water and food contamination.
-
Malaria - A parasitic disease spread by a mosquito bite.
-
Dengue - A viral disease spread by mosquito bites.
-
Typhoid - A bacterial infection.
-
Schistosomiasis - A parasitic disease caused by blood flukes.
-
Chagas Disease - A life-threatening parasitic disease that occurs in animals and humans.
-
Lymphatic filariasis - A parasitic disease that causes disfigurement of the legs.
-
Trachoma - An eye infection caused by bacteria.
Of all the diseases mentioned above, a few of them, like lymphatic filariasis, trachoma, and mycobacterial ulcer, come under the neglected tropical diseases. There are hundreds of other tropical diseases too. They are rare, and not much importance is given to them. A preventive strategy is planned for common tropical diseases.
How to Manage the Diseases Occurring in the Tropical Region?
The diagnosis and treatment for some of the common and neglected tropical diseases are as follows:
Tropical Ulcer: Tropical ulcer is a bacterial infection caused due to flies, friction, lack of food, and fuso-spirochetal (fusiform and spirochetal bacteria) organisms. It occurs on the lower leg and starts as a raised lesion on the skin and gradually progresses to form an ulcer. This ulcer, if left untreated, will become more infected and cause pain.
The treatment aims to remove the infected material and improve the healing process. To reduce the infection, antibiotic medicines are prescribed by the doctor for a few days. Later, surgical debridement of the ulcer is done. Surgical debridement is done under local anesthesia. The skin around the wound is cleaned, and the depth of the wound is visualized by probing with a metal instrument. A sharp instrument like a scalpel blade removes dead and infected tissues, which are then washed away. A dressing is placed over the wound and closed with bandages to allow healing.
In cases of ulcers that have been present for a long time, a biopsy (a portion of cells or tissue from the affected area is removed and observed under a microscope) is performed to detect cancer.
Mycobacterial Ulcer or Buruli Ulcer: It is common in Australia, Uganda, and Papua New Guinea. Mycobacterium ulcerans is the bacteria responsible for the disease. The lesion starts as a nodule (like a lump) and progresses into an ulcer. The ulcer grows in the margins of the ulcer, and healing occurs in the center. Lab tests confirm the bacteria by taking a sample of the ulcer.
The treatment for the ulcer is wound debridement and skin grafting to close the wound. Skin grafting takes a portion of the skin from a different part of the body and places it over the wound. The affected leg is immobilized with a plaster cast to promote healing.
The doctor prescribes medications like Streptomycin and Rifampicin for eight weeks to reduce the infection.
Fournier’s Gangrene: It is an infection that occurs in the scrotal region and is associated with multiple organs getting affected. The infection presents with pain, swelling, fever, skin discoloration, and itching in the affected area.
Treatment involves surgical debridement to remove the infected material from the wound. The doctor prescribes antibiotics.
Another treatment to improve the healing is by using hyperbaric oxygen therapy. Here, 100 percent oxygen is delivered to the wound to promote healing.
Cancrum Oris: The gangrenous infection is prevalent in West Africa. It occurs in children who are malnourished or lack oral hygiene maintenance. The bacteria responsible are Fusiform bacilli and Spirochetes. The disease starts as an ulcer within the mouth and continues to grow outwards, involving the cheek and parts of the face. Severe facial disfigurement is present, which makes the reconstruction quite challenging.
The treatment is started with antibiotics. The infected area is removed and reapproximated using skin grafts or flaps (healthy tissue) from the adjacent area.
Pyomyositis: The bacteria causing this infection are Streptococcus pyogenes and Escherichia coli. It is an infection of the skeletal muscle that more frequently occurs in males and those with weakened immunity. It affects the heavy muscles of the legs, hands, and the center part of the body. Diagnostic tests like ultrasonography (an imaging technique that uses sound waves to produce images of the body's internal structures) and pus aspiration can help confirm the disease. The doctor prescribes antibiotics and drains the pus carefully.
Tuberculosis: Tuberculosis of the breast is common in India, Africa, and Hong Kong. It affects young women between 20 to 30 years of age. The condition presents with a lump, nipple retraction, or hard swellings near the armpit region. When these signs are noted early, the doctor must be consulted to perform a fine needle aspiration biopsy (a sample of tissue taken using a needle to examine the cells in detail) to rule out the presence of cancer. Another type of tuberculosis common in the tropics occurs in the abdominal region. The affected person has abdominal swellings along with pain. Aspiration of the fluid from the affected area helps in confirming the diagnosis.
The treatment for tuberculosis of the breast and abdomen is chemotherapy. The patient is started with the therapy that continues for several months. Regular follow-ups with the doctor to check the treatment progress must be maintained.
If the medical therapy fails to treat the condition, surgically removing the affected part under general anesthesia is planned.
Filariasis: It is one of the neglected tropical diseases caused by a parasite, Wuchereria bancrofti. It affects the lymphatic vessels (that carry the white blood cells) of the legs and scrotum. A very large swelling of the lower leg occurs, known as elephantiasis. Since the lymphatics in the kidneys also get obstructed, milky urine is observed. Laboratory tests are carried out to confirm the diagnosis.
The treatment is initiated with medication to kill the parasites. The elephantiasis is treated by compression stockings (tight elastic socks that cover the leg to improve circulation) that exert pressure of 40 mmHg. In complicated cases, surgery is the only option.
Surgery involves the removal of the swollen area of the leg and reconstruction using skin grafts. The lymphatic vessels are removed and reapproximated with the adjacent lymph vessels.
In the affected lymphatics within the kidney, sclerotherapy is performed, wherein a solution containing 5 percent nitrate is injected to close the affected vessels.
A few common diseases that occur in the tropical region and their management have been described. The patient must be educated about the prevalent conditions and certain measures to maintain proper hygiene.
Conclusion
The tropical diseases that are unique to their region must be brought to the doctor’s notice as soon as possible to provide early intervention for the disease. The surgeon must be skilled enough to handle the patients who report to them at an early or advanced stage and provide appropriate treatment. An interdisciplinary approach is necessary with specialties from various departments to diagnose the disease and provide a successful outcome.
