By Sarah Hannan
With the third case of Trypanosoma infection reported in March from a Vet Clinic in Kadawatha, Peradeniya Veterinary Hospital is urging the public to be vigilant, especially if a pet canine falls ill.
While the first case of Human Trypanosomiasis was detected in 1999, and with the recent resurfacing of Animal Trypanosoma reported in three dogs, the Clinical Studies Department is now on alert as there might be a resurfacing of Human Trypanosomiasis.
“We have established through our tests that the parasite is T. Evansi. However, we are yet to identify the vector that is spreading the disease. We are now collecting samples of insects, frogs, and rats for research and test purposes in areas where the subjects were picked up,” Veterinary Clinical Studies Senior Professor Ashoka Dangolla stated.
The first incident
In Sri Lanka, since its first detection in 1999 in a farmer from Kalmunai, the disease seemed to be an isolated case. At the time Prof. Saroj Jayasinghe had published an article in the 44th volume of the Ceylon Medical Journal, printed in 1999, under the title “Sleeping Sickness Strikes Sri Lanka”, where he reported that the parasite was detected during an MRI scan and a blood sample was sent overseas for testing.
However, in the MBBS curriculum formulated at the University of Kelaniya Faculty of Medicine in 1995, the Department of Parasitology lecturers had viewed the importance of including diseases that are of major importance in a global context.
Therefore, students have been offered a 45-minute lecture on Trypanosomiasis and are taught to recognise a trypomastigote in a blood film to identify the parasite which could accidently infect humans.
With the above knowledge, health sciences undergraduate Lilanka Wijesundara was able to run the procedure on blood smears obtained from the dogs that were admitted to the Veterinary Teaching Hospital, Peradeniya. Wijesundara shared two case studies following that.
Case study 1: A male German Shepherd of one-and-a-half years from Balangoda was referred by the local veterinarian to the Veterinary Teaching Hospital, Peradeniya. The complaint was bilateral anterior chamber cloudiness in the eyes and keratitis. He was completely blind and nothing else was abnormal. His random blood sugar level was normal upon testing. Also the behaviour and appetite was normal according to the pre-clinical history.
The thin blood smear which was prepared from a sample of blood of the dog was found to be positive for Trypanosoma. At the time, “Berenil”, which was a drug given for trypanosomiasis, was not available at the Veterinary Teaching Hospital, Peradeniya.
Hence the dog was transferred to another veterinarian in Colombo for treatment. They had administered “Berenil”, which is the specific treatment. But the dog had not responded. However, suddenly, the dog died after a week of the treatment.
Case study 2: Another four-year-old, male German Shepherd from Mullaitivu was referred to the Veterinary Teaching Hospital, Peradeniya on 19 December 2018 with the complain of bilateral anterior chamber cloudiness and keratitis in the eyes.
Sudden blindness had occurred two weeks following hospitalisation. The dog’s red blood cell count, Hematocrit count and Hemoglobin levels were recorded to be low. When a thin blood smear was prepared, it was highly positive for Trypanosoma. The dog was treated with “Berenil” and a blood sample was again checked for trypanosome on 27 December 2018. The Trypanosoma parasite was not present in the sample and the treatment was successful. A blood sample has been submitted to veterinary parasitology for morphological and molecular identification.
When contacted by The Sunday Morning recently, Wijesundara stated that based on the above case studies, he would be presenting a paper on the Trypanosoma infection that surfaced in Sri Lanka over the past six to eight months.
“The proposal for the paper has been submitted and I am awaiting feedback from my lecturers. Once I get their feedback, I would be able to present the paper with the revisions.”
Headline: Human African trypanosomiasis aka sleeping sickness
According to the World Health Organisation (WHO), sleeping sickness is endemic in 36 sub-Saharan African countries where there are tsetse flies that transmit the disease.
Human African trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease. It is caused by infection with protozoan parasites belonging to the genus Trypanosoma. They are transmitted to humans by tsetse fly (Glossina genus) bites which have acquired their infection from human beings or from animals harbouring human pathogenic parasites.
Human African trypanosomiasis takes two forms, depending on the parasite involved:
· Trypanosoma brucei gambiense is found in 24 countries in west and central Africa. This form currently accounts for 98% of reported cases of sleeping sickness and causes a chronic infection. A person can be infected for months or even years without major signs or symptoms of the disease. When more evident symptoms emerge, the patient is often already in an advanced disease stage where the central nervous system is affected.
· Trypanosoma brucei rhodesiense is found in 13 countries in eastern and southern Africa. Nowadays, this form represents fewer than 2% of reported cases and causes an acute infection. First signs and symptoms are observed a few months or weeks after infection. The disease develops rapidly and invades the central nervous system. Only Uganda presents both forms of the disease, but in separate zones.
Another form of trypanosomiasis occurs mainly in Latin America. It is known as American trypanosomiasis or Chagas disease. The causal organism belongs to a different Trypanosoma subgenus and is transmitted by a different vector.
Sleeping sickness threatens millions of people in 36 countries in sub-Saharan Africa. Many of the affected populations live in remote rural areas with limited access to adequate health services, which complicates the surveillance and therefore the diagnosis and treatment of cases. In addition, displacement of populations, war and poverty are important factors that facilitate transmission.
· In 1998, almost 40,000 cases were reported, but estimates were that 300,000 cases were undiagnosed and therefore untreated.
· During the most recent epidemic, the prevalence reached 50% in several villages in Angola, the Democratic Republic of the Congo, and South Sudan. Sleeping sickness was the first or second greatest cause of mortality in those communities, even ahead of HIV/AIDS.
· In 2009, after continued control efforts, the number of cases reported dropped below 10,000 (9,878) for the first time in 50 years. This decline in number of cases has continued with 1,446 new cases reported in 2017 – the lowest level since the start of systematic global data-collection 80 years ago. The estimated number of actual cases is below 10,000 and the estimated population at risk is 65 million people.
The disease is mostly transmitted through the bite of an infected tsetse fly but there are other ways in which people are infected:
· Mother-to-child infection: The trypanosome can cross the placenta and infect the fetus.
· Mechanical transmission through other blood-sucking insects is possible. However, it is difficult to assess its epidemiological impact.
· Accidental infections have occurred in laboratories due to pricks with contaminated needles.
· Transmission of the parasite through sexual contact has been documented.
In the first stage, the trypanosomes multiply in subcutaneous tissues, blood, and lymph. This is also called haemo-lymphatic stage, which entails bouts of fever, headaches, joint pains, and itching
In the second stage the parasites cross the blood-brain barrier to infect the central nervous system. This is known as the neurological or meningo-encephalic stage. In general, this is when more obvious signs and symptoms of the disease appear – changes of behaviour, confusion, sensory disturbances, and poor coordination. Disturbance of the sleep cycle, which gives the disease its name, is an important feature. Without treatment, sleeping sickness is considered fatal, although cases of healthy carriers have been reported.
Source: WHO
With the third case of Trypanosoma infection reported in March from a Vet Clinic in Kadawatha, Peradeniya Veterinary Hospital is urging the public to be vigilant, especially if a pet canine falls ill.
While the first case of Human Trypanosomiasis was detected in 1999, and with the recent resurfacing of Animal Trypanosoma reported in three dogs, the Clinical Studies Department is now on alert as there might be a resurfacing of Human Trypanosomiasis.
“We have established through our tests that the parasite is T. Evansi. However, we are yet to identify the vector that is spreading the disease. We are now collecting samples of insects, frogs, and rats for research and test purposes in areas where the subjects were picked up,” Veterinary Clinical Studies Senior Professor Ashoka Dangolla stated.
The first incident
In Sri Lanka, since its first detection in 1999 in a farmer from Kalmunai, the disease seemed to be an isolated case. At the time Prof. Saroj Jayasinghe had published an article in the 44th volume of the Ceylon Medical Journal, printed in 1999, under the title “Sleeping Sickness Strikes Sri Lanka”, where he reported that the parasite was detected during an MRI scan and a blood sample was sent overseas for testing.
However, in the MBBS curriculum formulated at the University of Kelaniya Faculty of Medicine in 1995, the Department of Parasitology lecturers had viewed the importance of including diseases that are of major importance in a global context.
Therefore, students have been offered a 45-minute lecture on Trypanosomiasis and are taught to recognise a trypomastigote in a blood film to identify the parasite which could accidently infect humans.
With the above knowledge, health sciences undergraduate Lilanka Wijesundara was able to run the procedure on blood smears obtained from the dogs that were admitted to the Veterinary Teaching Hospital, Peradeniya. Wijesundara shared two case studies following that.
Case study 1: A male German Shepherd of one-and-a-half years from Balangoda was referred by the local veterinarian to the Veterinary Teaching Hospital, Peradeniya. The complaint was bilateral anterior chamber cloudiness in the eyes and keratitis. He was completely blind and nothing else was abnormal. His random blood sugar level was normal upon testing. Also the behaviour and appetite was normal according to the pre-clinical history.
The thin blood smear which was prepared from a sample of blood of the dog was found to be positive for Trypanosoma. At the time, “Berenil”, which was a drug given for trypanosomiasis, was not available at the Veterinary Teaching Hospital, Peradeniya.
Hence the dog was transferred to another veterinarian in Colombo for treatment. They had administered “Berenil”, which is the specific treatment. But the dog had not responded. However, suddenly, the dog died after a week of the treatment.
Case study 2: Another four-year-old, male German Shepherd from Mullaitivu was referred to the Veterinary Teaching Hospital, Peradeniya on 19 December 2018 with the complain of bilateral anterior chamber cloudiness and keratitis in the eyes.
Sudden blindness had occurred two weeks following hospitalisation. The dog’s red blood cell count, Hematocrit count and Hemoglobin levels were recorded to be low. When a thin blood smear was prepared, it was highly positive for Trypanosoma. The dog was treated with “Berenil” and a blood sample was again checked for trypanosome on 27 December 2018. The Trypanosoma parasite was not present in the sample and the treatment was successful. A blood sample has been submitted to veterinary parasitology for morphological and molecular identification.
When contacted by The Sunday Morning recently, Wijesundara stated that based on the above case studies, he would be presenting a paper on the Trypanosoma infection that surfaced in Sri Lanka over the past six to eight months.
“The proposal for the paper has been submitted and I am awaiting feedback from my lecturers. Once I get their feedback, I would be able to present the paper with the revisions.”
Headline: Human African trypanosomiasis aka sleeping sickness
According to the World Health Organisation (WHO), sleeping sickness is endemic in 36 sub-Saharan African countries where there are tsetse flies that transmit the disease.
Human African trypanosomiasis, also known as sleeping sickness, is a vector-borne parasitic disease. It is caused by infection with protozoan parasites belonging to the genus Trypanosoma. They are transmitted to humans by tsetse fly (Glossina genus) bites which have acquired their infection from human beings or from animals harbouring human pathogenic parasites.
Human African trypanosomiasis takes two forms, depending on the parasite involved:
· Trypanosoma brucei gambiense is found in 24 countries in west and central Africa. This form currently accounts for 98% of reported cases of sleeping sickness and causes a chronic infection. A person can be infected for months or even years without major signs or symptoms of the disease. When more evident symptoms emerge, the patient is often already in an advanced disease stage where the central nervous system is affected.
· Trypanosoma brucei rhodesiense is found in 13 countries in eastern and southern Africa. Nowadays, this form represents fewer than 2% of reported cases and causes an acute infection. First signs and symptoms are observed a few months or weeks after infection. The disease develops rapidly and invades the central nervous system. Only Uganda presents both forms of the disease, but in separate zones.
Another form of trypanosomiasis occurs mainly in Latin America. It is known as American trypanosomiasis or Chagas disease. The causal organism belongs to a different Trypanosoma subgenus and is transmitted by a different vector.
Sleeping sickness threatens millions of people in 36 countries in sub-Saharan Africa. Many of the affected populations live in remote rural areas with limited access to adequate health services, which complicates the surveillance and therefore the diagnosis and treatment of cases. In addition, displacement of populations, war and poverty are important factors that facilitate transmission.
· In 1998, almost 40,000 cases were reported, but estimates were that 300,000 cases were undiagnosed and therefore untreated.
· During the most recent epidemic, the prevalence reached 50% in several villages in Angola, the Democratic Republic of the Congo, and South Sudan. Sleeping sickness was the first or second greatest cause of mortality in those communities, even ahead of HIV/AIDS.
· In 2009, after continued control efforts, the number of cases reported dropped below 10,000 (9,878) for the first time in 50 years. This decline in number of cases has continued with 1,446 new cases reported in 2017 – the lowest level since the start of systematic global data-collection 80 years ago. The estimated number of actual cases is below 10,000 and the estimated population at risk is 65 million people.
The disease is mostly transmitted through the bite of an infected tsetse fly but there are other ways in which people are infected:
· Mother-to-child infection: The trypanosome can cross the placenta and infect the fetus.
· Mechanical transmission through other blood-sucking insects is possible. However, it is difficult to assess its epidemiological impact.
· Accidental infections have occurred in laboratories due to pricks with contaminated needles.
· Transmission of the parasite through sexual contact has been documented.
In the first stage, the trypanosomes multiply in subcutaneous tissues, blood, and lymph. This is also called haemo-lymphatic stage, which entails bouts of fever, headaches, joint pains, and itching
In the second stage the parasites cross the blood-brain barrier to infect the central nervous system. This is known as the neurological or meningo-encephalic stage. In general, this is when more obvious signs and symptoms of the disease appear – changes of behaviour, confusion, sensory disturbances, and poor coordination. Disturbance of the sleep cycle, which gives the disease its name, is an important feature. Without treatment, sleeping sickness is considered fatal, although cases of healthy carriers have been reported.
Source: WHO