Hansen’s disease, commonly called leprosy, is a slightly infectious, chronic disease caused by bacteria called Mycobacterium leprae. This germ was discovered in Bergen, Norway in 1873 by Dr. Gerhard Armauer Hansen. The germ attacks mainly the skin, nerves and mucus membranes.
Involvement of the skin may result in several types of skin lesions that may easily be mistaken for other more common skin conditions. Nerve involvement may cause nerve damage that may result in loss of feelings in the hands, feet and eyes. The affected person may suffer from frequent painless injuries and burns in the hands, feet and eyes. The injuries may heal with scarring. When this occurs repeatedly, it may result in absorption of the digits in the hands and feet and blindness in the eyes. In later stages nerve damage may even result in muscle weakness progressing to wasting and paralysis of the muscles of the hands, feet and eyelids. Damage to bones may cause collapse of the bridge of the nose and loosening of the upper front teeth. Involvement of the mucous membrane of the upper respiratory tract may result in progressive non-responsive stuffiness of the nose, loss of the sense of smell and in some severe cases hoarseness of voice.
Hansen’s disease can be cured with the modern-day Multiple Drug Therapy (MDT) in any stage of the disease. However, if nerve damage has already occurred by the time the disease is recognized and treated, recovery of nerve function may only occur if the nerve damage is less than 6 months in duration. If Hansen’s disease is not treated, it may continue to progress and cause severe, distressing and stigmatizing disabilities secondary to nerve and bone damage.
Treating the patient early will not only prevent nerve and bone damage but will also prevent the spread of the disease.
Transmission of Hansen's Disease
Humans are the only source of infection. However, there are reports that the disease had once been acquired from nine banded armadillos in the southern states of America. Never the less, It is mainly transmitted from the nose and throat while coughing and sneezing or by skin-to-skin contact, with entry through a broken skin of an untreated person during close and prolonged contact.
Hansen’s disease is not hereditary and is not transmitted sexually. It is considered to be a chronic disease because it starts slowly and lasts for a long time. This is mostly because Mycobacterium leprae multiplies once every 12 days, unlike other bacteria or viruses that multiply within minutes. The incubation period, which is the time from acquiring the infective organism to the time signs and symptoms of the disease appear, for Hansen’s disease is usually 2 – 5 years. There have also been reports of periods varying from 1 year to 20 years or even more.
Type and Treatment of Hansen's Disease
Most commonly, only one type of Mycobacterium leprae causes Hansen’s disease, yet, no two patients with the same diagnosis of Hansen’s disease will have the same type of lesions. This is mainly because of the difference in each individual’s body resistance specific to the germ Mycobacterium leprae.
If the individual has complete body resistance to the germ, the person will kill all the germs, so there will be no Hansen’s disease. If the individual has a strong but not complete body resistance to the germ, majority of the germs will be killed and only some will not be killed hence, the individual will develop just a few numb patches on the skin. If the individual has a moderate level of body resistance to the germ, some germs will be killed but quite many will not be killed. Such an individual may get numerous lesions, some flat, some with a thin raised border resembling a ringworm like lesion and some with wide raised borders. It is very likely such an individual may also have nerve involvement as well. Some individuals with this type of the disease may also complain of long standing stuffiness of the nose that does not respond to nasal drops for allergy. This type is not stable. It can suddenly either change to the less severe type or worsen to a more severe type.
Finally, if the individual has no resistance or poor resistance to the germ, the germs will multiply unchecked and spread from head to toe. Such an individual may get multiple raised rounded lesions on the ear lobules, face and limbs. All such lesions may be loaded with the germ. Ironically, though their nerves too may be teeming with the germs and may even be thickened, they may have no evidence of loss of nerve function. Loss of nerve function may appear after they start treatment. Such an individual is also very likely to suffer from long standing stuffiness of the nose that does not respond to nasal drops for allergy. Such an individual is likely to spread the germs to others who are in their close proximity for prolonged periods.
Overall, individuals who can spread the germs to others form a mere 10% to 15% of all who suffer from Hansen’s disease. Even such an individual becomes non-contagious after the very first dose of MDT. The remaining cases are non-contagious even without treatment. However, without treatment their disease may continue to worsen.
Signs or Symptoms of Hansen's Disease
- The skin manifestation of Hansen’s disease can vary greatly from one patient to another.
- The early lesion may look like a light-colored patch on a colored skin or a slightly reddish patch on a light-colored skin. It may look like the ordinary lota (pityriasis versicolor) but it does not respond to anti-fungal or even anti-eczema medicines that are applied locally to the skin or even if given orally. There may be decreased hair growth on the patch compared to the surrounding normal skin. The patch may also appear dry due to impaired sweating. Later, the patch may have loss of feeling to light touch or lack of pain on pin prick. In short, the patch will have:
- Lack of normal density of hair
- Diminished or reduced feelings on a patch (not just on an area of normal looking skin), is diagnostic of Hansen’s disease.
- Some cases may have nodules (lumps) on the ears, eyebrows, nose and limbs. The trunks may have flat or barely raised lesions.
- Some cases may have infiltration (thickened and raised areas) in the skin of the face, especially the eyebrows & ear lobules, limbs and other parts of the body with sparing of armpits and groins.
- Loss of feelings on the hands and feet resulting in frequent painless burns and injuries.
- Loss of feelings on the corneal (the transparent cover of the eye) may lead to painless eye ulcer and eventually blindness.
- Weakness of the muscles of the hands, feet and eyelids with muscle wasting and paralysis in later stages.
- Damage to the nerve by the knee may cause a foot-drop resulting in a high stepping gait on the affected side.
- Damage to the nerve by the elbow may cause claw hand deformity resulting in weakness or inability to grasp any object.
- Damage to nerves of the eyelids may cause inability to blink or close the eyes. The person may sleep with eyes wide open.
- Dryness of the hands and / or feet due to loss of sweating.
All these damages are preventable if the disease is identified and treated early.
Diagnostic Signs of Hansen’s Disease
Presence of at least 1 of the 3 criteria listed below:
- Light or reddish colored spot on the skin with some loss of feeling to touch and pinprick
- Enlarged or painful peripheral nerve with loss of sensation with or without muscle weakness in the muscle supplied by the nerve
- Presence of AFB on skin smears or biopsy
WHO Classification of the Disease
For treatment purpose, all cases of Hansen’s disease are classified as either Paucibacillary (PB) cases or Multibacillary (MB) cases.
- A Paucibacillary case is a patient with up to five skin lesions and the slit skin smears and skin biopsy are negative for AFB (an abbreviation for Acid Fast Bacilli; named after the staining property of the germ).
- A Multibacillary case is a patient with more than five skin lesions and/or is positive for AFB on slit skin smears and/or skin biopsy.
Multiple Drug Therapy
Trinidad and Tobago introduced the World Health Organization (WHO) recommended Multi Drug Therapy (MDT) in 1982. However, the drug regimen as well as the total duration of treatment has changed over time. The current WHO recommendation is that both PB cases as well as MB cases receive the same 3 drugs. The only difference is that the PB cases receive the 3 drugs for 6 months while the MB cases receive the 3 drugs for 12 months.
The treatment is free of cost and easily available. It is safe and can even be given to a pregnant lady or a nursing mother.
Modern MDT is so effective that just the first dose of MDT renders the person non-contagious. The danger of catching the disease is only possible from cases (10 -15% of all cases) who are still not on treatment.
Once the patient completes the recommended duration of treatment; the MDT is stopped and the patient is declared as being ‘Released from Treatment’ (RFT) but continues to be under surveillance. It is quite frequent that certain MB cases may present with an immunological phenomenon known as ‘Reaction’ prior to the onset of MDT or during the course of MDT and may therefore also need other drugs to suppress the reaction. If, even after being declared to be RFT, any individual who may still have manifestations of the ‘reaction’ may need to visit the clinic more frequently and continue with the treatment for ‘reaction’ till it goes into total remission.
All RFT patients are advised to visit the clinic every 6 months for 3 years for the PB cases and for 5 years for the MB cases. This is called the surveillance period. During this period the patients are examined to determine whether the skin lesions are continuing to clear up satisfactorily and to make sure that there are no new complaints or lesions.
A few MB patients may develop a ‘reaction’ for the first time after being declared as being RFT. Such patients may require more frequent visits to the clinic and treatment with other drugs to suppress the ‘reaction’ till it undergoes complete remission. At the end of 3 or 5 years of surveillance, they are discharged from the clinic if they are well. Patients are advised to visit the clinics if they have any skin or nerve problem. Other than that, they are to visit their nearest health center for non-skin problems.
For more than 40 years, MDT has had an unparalleled record of success in terms of efficacy, safety and the prevention of the emergence of resistant strains. After reaching the stage of having the new case detection rate to less than 1 per 10,000 population every year, case detection became voluntary or ‘passive’; that is, the Hansen’s Disease Control Unit (HDCU) did not conduct house to house examination to detect Hansen’s disease case.
However, in spite of having a highly effective treatment for Hansen’s disease, new case detection rates did not reduce at the same rate as it did in the 1990s. For this reason, the World Health Organization now recommends active case finding in pockets that show higher occurrence of new cases. In Trinidad and Tobago, such pockets will be identified by mapping all the new cases detected in the past 8 to 10 years with the help of the Ministry’s Geographic Information System (GIS).
From 2021, HDCU will launch active case finding in such pockets. The residents of those pockets who are found to have Hansen’s disease, will be offered the complete treatment regimen. Those residents who do not have clinical evidence of Hansen disease will be offered the Single Dose Rifampicin (an antibiotic) as a preventative measure after proper evaluation of eligibility (see ‘Contact Tracing’ & ‘Prophylaxis’ below). Administering rifampicin to an apparently healthy resident will be on strict voluntary basis.
Based on several studies and field experience, WHO has stated that household contacts of multi-bacillary (MB) Hansen’s disease patients have a 5-to-8-fold increased risk of developing Hansen’s disease compared with individuals not living in such dwellings; while the likelihood of developing Hansen’s disease in household contacts of pauci-bacillary (PB) cases is almost double than that in the general community. This has also been borne out by the data collected in the past 10 years by HDCU that routinely screens all household contacts, neighborhood contacts, as well as, social contacts of an individual suffering with Hansen’s disease. This is done to pick any contact who already has the clinical evidence of the disease and to promptly administer the full MDT regimen. WHO has proposed that any individual who has spent 20 hours a week, for 3 months in a year, with a case of Hansen’s disease should be considered to have prolonged contact with the disease. Such an individual must be screened for clinical evidence of Hansen’s disease.
By the year 2005, the introduction of MDT in the management of Hansen’s disease brought a dramatic reduction in the number of new cases detected annually to less than 1 per 10,000 population in all countries. After that, the decline in the new case detection was very slow. From 2009 to 2018 the decline in global new case detection rate was a mere 2%. Every year about 200,000 new cases are detected globally. This means that every 2 minutes someone, somewhere in the world is diagnosed with Hansen’s disease.
In Trinidad and Tobago too, the annual rate of new case detection has remained within the range of 25 to 30 cases. It is worthwhile to state that a little more than 55% of cases detected in 2020 had from 1 up to 7 members of their family treated for Hansen’s disease in the past! Looking at the high rate of occurrence of the disease in contacts of those suffering with Hansen’s disease, it is obvious that if there is an effective measure of prevention for such contacts, it could significantly reduce the number of new cases detected every year.
Based on the results of several studies and field experience on the efficacy and feasibility of different means of prophylaxis, the WHO Guidelines for the diagnosis, treatment and prevention of leprosy (2018) recommends incorporation of Single Dose of Rifampicin (SDR) as a Post Exposure Prophylaxis (SDR – PEP) to all contacts into the routine activities of all Hansen’s Disease Control Programs. Subsequently in 2020 WHO published the technical guidance on Leprosy/Hansen disease: Contact tracing and post-exposure prophylaxis thatrecommends active case finding and also documents the results of various studies done on the subject of SDR-PEP and also details the steps for implementing and recording the strategy.
In other words, a single dose of Rifampicin (an antibiotic) will be offered to all household, neighborhood and social contacts of persons suffering with Hansen’s disease to protect them from the risk of developing the disease in later years. Several studies have shown that this reduces their risk of developing the disease by up to 60%. From 2021 HDCU will start offering SDR-PEP to all contacts of cases detected from 2019 to date. It is worth mentioning once again that administering the single dose of rifampicin to clinically healthy contacts of cases suffering from Hansen’s disease will be strictly on voluntary basis. Unfortunately, as of now (June 2021), we still do not have an effective vaccine for the prevention of Hansen’s disease.
Schedule of the Joint Hansen’s Disease and Dermatology Clinic
In Trinidad and Tobago, Hansen’s disease is treated at the Joint Hansen’s Disease/Dermatology clinics run by the Ministry of Health’s Hansen’s Disease Control Unit (HDCU). Clinic schedule is as follows:
- Arima Health Facility - 1st and 3rd Wednesday
- Chaguanas Health Centre - 2nd and 4th Friday
- George Street Health Centre - 2nd and 4th Thursday
- San Fernando General Hospital (Ward 17) - 1st and 3rd Tuesday
- Sangre Grande Health Centre - 2nd and 4th Tuesday
- St. Joseph Health Centre - 2nd and 4th Monday
All clinics start at 8:00 a.m. with the exception of St. Joseph health Centre, which begin at 11:00 a.m.
Head Office Hansen’s Disease Control Unit
182 Western Main Road,
Tel. #: (868)-622-3904