WEEKLY EPIDEMIOLOGICAL REPORT A publication of the Epidemiology Unit Ministry of Health & Indigenous Medical Services 231, de Saram Place, Colombo 01000, Sri Lanka Tele: + 94 11 2695112, Fax: +94 11 2696583, E mail: [email protected] Epidemiologist: +94 11 2681548, E mail: [email protected] Web: http://www.epid.gov.lk Vol. 47 No. 33 08th– 14th Aug 2020 Neglected Tropical Diseases - Dracunculiasis (Guinea-worm disease) Dracunculiasis (Guinea-worm disease) Dracunculiasis is a parasitic illness at the brink of eradication, with only 54 cases reported in 2019. These 54 were reported from 4 African countries. The parasite enters the human body through ingestion of water contaminated with fleas that are infected with the parasite. The water fleas are killed in the stomach, liberating which interprets as they acquire infection in the the larvae inside them. These larvae penetrate same way as other intermediate hosts but are the intestine wall and migrate within tissues, and not involved in transmitting the infection to the in the process grow to their full size (60-100cm). definitive host. The disease is transmitted to The fertilized adult female worm emerges from humans through ingestion of food, water or soil its exit –usually a lower limb, where it forms a contaminated with the parasite eggs, or after painful blister. When infected persons immerse direct contact with animal hosts. There are 4 their legs in water to soothe the pain, the worm forms of Echinococcosis, each caused by a dif- releases its larvae into the water. These larvae ferent organism of the genus Echinococcus: are ingested by tiny crustaceans known as water Form Causative organism fleas, where they mature into their infective cystic echinococ- stage. This process takes about 10-14 months. cosis SRI LANKA 2020 Echinococcus granu- Even though the disease is rarely fatal, it ren- also known as hydatid losus; disease or hydatidosis ders those who are infected non-functional for weeks. The disease has no specific treatment. It alveolar echinococ- E. multilocularis cosis is however preventable. Successful preventive neotropical echinococ- E. vogeli techniques such a behavioural change, source cosi unicystic E. oligarthrus control, environmental (water) sanitation, vector control and heightened surveillance has brought The two most important forms, which are of this crippling disease close to eradication medical and public health relevance in humans, are cystic echinococcosis (CE) and alveolar Echinococcosis echinococcosis (AE). Infection with E. granu- Echinococcosis is a parasitic illness caused by a losus results in the development of one or more tape-worm species of the genus Echinococcus. hydatid cysts in humans, most commonly in the A number of herbivorous and omnivorous ani- liver and lungs. The cysts can grow for years mals serve as intermediate hosts of the parasite, undetected until they become large enough to while carnivorous animals act as definitive hosts. produce symptoms. Cysts in the liver can result Humans are an accidental intermediate host, in abdominal pain, nausea and vomiting while Contents Page 1. Leading Article – Neglected Tropical Diseases - Dracunculiasis (Guinea-worm disease) 1 2. Summary of selected notifiable diseases reported (01st– 07th August 2020) 3 3. Surveillance of vaccine preventable diseases & AFP (01st– 07th August 2020) 4 WER Sri Lanka - Vol. 47 No. 33 08th– 14th Aug 2020 those in lungs can lead to chronic cough, chest pain and short- ness of breath. In infection with E. multilocularis, patients re- main asymptomatic for 5-15 years, which is followed by the development of a slow growing tumour-like lesion, usually in the liver. The disease is detected by radiological investigations i.e. ultrasonography and X-ray. The disease requires complex treatment which includes: chemotherapy, percutaneous treat- ment of hydatic cysts; surgery is the definitive treatment. Figure- Tsetse fly With about 1 milllion prevalent cases worldwide at any given time, Echinococcosis exerts a substantial burden in affected There are two types of the disease: i) Trypanosoma brucei countries. It is commonly seen in certain parts of South Ameri- gambiense which accounts for 98% of the reported cases; and ca, East Africa, Central Asia and China. Prevention and control ii) Trypanosoma brucei rhodesiense. The former causes chron- of Echinococcosis is a challenging task as the disease is ic infection which can extend up to months or years without asymptomatic in animals which have the most contact with manifesting symptoms and signs, while the latter causes a humans i.e. livestock and dogs. Cleanliness and proper sanita- more acute infection. tion during animal husbanry, deworming of dogs wherever pos- There are two stages in the disease course. In the first stage, sible are some examples of prevention and control. known as the haemo-lymphatic stage, the organisms multiply Foodborne trematodiasis within blood, lymph and subcutaneous tissues. This stage is characterized by the onset of bouts of fever, headache, lym- Foodborne trematode infections are primarily zoonotic diseas- phadenopathy, arthralgia and itching. The second stage, es caused by trematodes (i.e. flatworms/flukes) which are known as the neurological or meningo-encephalic stage, oc- transmitted to humans through the consumption of food con- curs when the organism crosses the blood-brain barrier and taminated with the parasite. These worms have a complex infects the central nervous system of the host. Changes of lifecycle involving intermediate hosts such as molluscs, crusta- behaviour, confusion, sensory disturbances, poor coordination ceans and fish. The infections are mostly mild in humans; how- and disturbance of the sleep cycle are characteristic features ever, there are 4 genera that cause severe disease: of this stage. Figure – Diagnosis of the disease is in 3 stages: Genus Disease food Clonorchis spp. Clonorchiasis • Screening for potential infection by serological testing Opisthorchis spp Opisthorchiasis borne (only available for T.b.gambiense) and checking for clinical Fasciola spp. Fascioliasis trema- Paragonimus spp. Paragonimiasis signs such as swollen cervical lymph nodes. tode in- fections with severe pathology in humans • Diagnosing by establishing whether the parasite is present in body fluids. These infections are commonly seen in East and South-East Staging to determine the state of disease progression. This Asia, consistent with the diets containing raw fish and crusta- consists of clinical examination and cerebrospinal fluid analysis The mode of treatment is based on the stage of the disease: ceans in these regions. It is estimated that over 40 million peo- Pentamidine and Suramin are used in the first stage and drugs ple are affected world over. Adequate sanitation, behavioural such as melarsoprol, eflornithine, nifurtimox are used in the change, especially with regard to culinary practices and source second stage, while fexinidazole is a new drug which caters to control by treatment (praziquantel) are the mainstay modes of both stages. Prevention and control depend mainly on vector prevention and control. control and surveillance. Human African Trypanosomiasis (Sleeping Sickness) Compiled By Dr. Chathurika Herath, PG Trainee in Community Medicine, Sleeping sickness is a vector-borne parasitic disease caused Epidemiology Unit, Ministry of Health by a protozoan belonging to the genus Trypanosoma and References: mainly transmitted by the bite of tsetse flies. These flies are a World Health Organisation: Fact sheets on NTDs species of blood sucking flies which acquire the infection from https://www.who.int/news-room/fact-sheets/detail/dracunculiasis-(guinea-worm- infected humans/ other animals during feeding. Tsetse flies are disease) https://www.who.int/news-room/fact-sheets/detail/echinococcosis commonly seen in agricultural and rural settings in Sub- https://www.who.int/foodborne_trematode_infections/infections_more/en/ Saharan Africa. The disease also exhibits other modes of https://www.who.int/news-room/fact-sheets/detail/trypanosomiasis-human-african transmission via blood and blood products as well. -(sleeping-sickness) Page 2 WER Table RDHS Dengue Fever Dysentery Encepha Enteric Food Leptospiro Typhus Viral Human Chickenpox Meningitis Leishmani- WRCD Division litis Fever Poisoning sis Fever Hepatitis Rabies asis 1 : Sri Lanka S A B A B T* C** A B A B A B A B A B A B A B A B A B A B elected notifiable diseases reported by Medical Officers of Health MedicalofHealth Officers reported by diseases elected notifiable Colombo 53 3585 0 22 0 9 0 5 0 14 3 226 0 2 0 3 0 0 1 185 1 34 0 2 56 100 Gampaha 31 2137 0 8 1 5 0 6 0 19 7 173 3 4 0 5 0 0 1 228 2 22 0 40 42 98 Kalutara 14 1519 0 10 0 5 0 4 0 4 15 490 0 13 0 5 0 0 3 254 0 33 0 0 51 100 - Kandy 105 2494 0 21 0 1 1 9 2 13 7 166 0 82 0 4 0 0 1 142 0 21 2 55 63 100 No. 33 47 Vol. Matale 4 527 1 7 0 3 0 5 0 6 2 87 0 6 0 7 0 1 0 47 0 2 7 221 63 100 NuwaraEliya 1 150 0 23 0 1 0 1 0 9 2 87 1 68 0 3 0 0 0 69 0 10 0 0 23 100 Galle 15 1485 0 27 0 17 0 4 0 14 19 500 3 48 0 3 0 0 2 279 2 43 0 4 30 99 Hambantota 3 317 0 7 0 4 0 2 1 44 1 169 3 46 0 2 0 1 0 155 1 38 18 495 68 100 Matara 3 464 0 21 0 14 0 1 0 3 4 382 2 10 0 7 0 0 1 114 1 17 11 288 16 100 Jaffna 6 1970 2 72 0 0 0 20 1 23 0 20 4 496 0 0 0 1 1 94 0 9 1 1 31 93 Kilinochchi 2 124 0 37 0 2 1 11 0 13 0 18 1 28 0 1 0 0 0 12 0 10 0 13 64 100 Mannar 0 130 0 0 0 0 0 1 0 2 0 6 0 2 0 0 0 0 0 2 1 7 0 0 39 100 Vavuniya 2 248 1 11 0 0 0 5 1 3 0 40 0 1 0 0 0 0 0 29 0 4 0 1 66 100 Mullaitivu