Showing posts with label Zoonotic Diseases. Show all posts
Showing posts with label Zoonotic Diseases. Show all posts

Friday, 25 July 2025

Four Human deaths from Rabies outbreak in Timor-Leste in May & June 2025.

Four Human deaths from Rabies have been confirmed in Timor-Leste (formerly East Timor) between 17 May and 17 June 2025, according to a bulletin issued by the World Health Orgnization on 24 July 2024. All four had been bitten by Dogs infected by the disease, and suffered syptoms including hydrophobia, photophobia, aggressiveness, convulsions, and hallucinations, and all four were subsequently confirmed as Rabies infections by Reverse Transcription Polymerase Chain Reaction testing at the National Health Laboratory.

The first fatality was an adult male from Ermera Municipality, who was bitten by a Dog in March 2025, and sought medical help on 15 May, subsequently dying in a hospital two days later. The second fatality, another adult male, this time from Oecusse Municipality, who was bitten by a Dog in June 20242, and arrived at a regional hospital with symptoms on 27 May 2024, subsequently dying on 30 May. The third case was another adult male, this time from Bobonaro Municipality, who arrived at a medical centre on 12 June 2025, having been bitten by a Dog 2-3 months earlier. This parient subsequently died on 13 June. The final case was a female child from Bobonaro Municipality, who was taken into medical care on 12 June 2025, having been bitten by a Dog about two months earlier. This patient subsequently died on 17 June. Two further Rabies fatalities were reported in Oecusse Municipality in 2024.

The outbreak appears to have begun in Dogs in Oecusse Municipality in March 2024, since when 103 Dogs have died from the disease in Oecusse and Bobonaro Municipalities, as well as two Goats, one each in Oecusse and Bobonaro, and a Pig in Bobinaro. Oecusse Municipality forms an enclave within Indonesia's East Nusa Tenggara Province, where Rabies is considered to be endemic and Human fatalities are frequently reported, with Bobonaro shares a border with the province. Ermera Municipality lacks a border with Indonesia, but borders Bobonaro.

The island of Timor showing the regions covered by Timor-Leste and East Nusa Tenggara Province. Google Maps.

The rising number of Rabies deaths in Timor-Leste suggests the disease is spreading across the its borders with Indonesia, pobably via infected Dogs, and becoming established within the smaller nation. The World Health Organization recomends that this is addressed through a combination of Dog vaccinations and education to raise public awareness of the disease. 

Between March 2024 and 15 June 2025, 1445 dog scratches and bites were reported in Timor-Leste, 41% of which were considered to by Catagoy III exposures, which is to say exposures in which the skin is broken and saliva from an Animal has come into contact with this break. World Health Organization guidelines recomend that in such cases the wound should be washed immediately and the patient should be given  immediate vaccination and administration of rabies immunoglobulin/monoclonal antibodies. Of the 1445 known Catagory III exposures in Timor-Leste in 2024 and 2025, only 66% began this course of vaccination and antibody administration, and only 18% completed the course.

Rabies is caused by Viruses of the genus Lyssavirus, a member of the Rhabdoviridae Family of negative-sense single-stranded RNA Viruses, which also includes pathogens attacking Fish, Insects and Plants. Rabies is spread through the saliva of infected animals, and causes hydrophobia (fear of water),  anxiety, insomnia, confusion, agitation, abnormal behaviour, paranoia, terror, and hallucinations, followed by paralysis, coma and death in Humans. Many animals (notably Dogs) become extremely aggressive at this stage and will bite anything that comes near them, helping to spread the disease. 

Transmission electron microscope image with numerous rabies virions (small, dark grey, rodlike particles) and Negri bodies (the larger pathognomonic cellular inclusions of rabies infection). Centers for Disease Control and Prevention/Wikimedia Commons.

In Humans, the disease typically has a gestation period of about three months, during which time the disease can be treated by repeated vaccination and doses of human rabies immunoglobulin, though if treatment is not begun within ten days of infection it is less likely to be successful, and once the patient starts to develop symptoms the disease is almost invariably fatal. Any wound thought to have been caused by an infected animal should be washed thoroughly under running water for at least five minutes, before being treated with alcohol or iodine, and immediate medical attention sought.

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Thursday, 7 November 2024

Malaria in Ethiopia.

Between 1 January and 20 October 2024 more than 7.4 million cases of Malaria were reported in Ethiopia, with 1157 deaths recorded, a case fatality rate of 0.02%, according to a press release issued by the World Health Organization on 31 October 2024. On these infections, 95% were causes by Plasmodium falciparum. This is the highest number of cases reported in Ethiopia in seven years, and part of an ongoing rising trend of Plasmodium falciparum infections; in 2023, 4.21 million Malaria infections, with 527 deaths, with 70% caused by Plasmodium falciparum.

The overwhelming majority of cases occurred in the west of the country, with four regions accounting for 81% of all recorded infections and 89% of known deaths, with 44% of cases and 667 deaths in Oromo, 18% of cases and 56 deaths in Amhara, 12% of cases and 250 deaths in Southwest Ethiopia, and 7% of cases and 45 deaths in South Ethiopia. 

Geographical distribution of Malaria cases as of 20 October 2024. World Health Organization.

Of Ethiopia's 523 worodas (districts), 222 have been identified as having a high Malaria burden, together accounting for 75% of recorded Malaria cases in 2023. Fifty of these high-burden worodas are considered to be hard-to-access due to ongoing conflicts.

A slight majority of cases are males, who accounted for 56% of cases treated as outpatients and 52% of inpatient admissions. Children accounted for 16% of outpatients and 25% of inpatient admissions. This age and sex distribution is thought to be due to patterns of seasonal migration, with large numbers of adult male migrant workers seeking work in high-risk areas during the peak of the Malaria season. 

From 2000-onwards, Ethiopia had a steady reduction in the number of Malaria cases each year, driven by improved surveillance, roll-out of malaria interventions, and community health extension program. The number of cases fell to an all-time low in 2019, when only 900 000 cases were recorded, and there was no wide-ranging major epidemic, only sporadic local outbreaks. However, the country began to suffer a resurgence of the disease from 2021 onwards, with 1.3 million cases in 2021, 3.3 million cases in 2022, and 4.1 million cases in 2023. This return appears to have been driven by the Plasmodium falciparum strain of the disease, which caused 70% of the infections in 2023, and which appears to have become endemic in areas where it was not previously known.

Weekly trend of malaria cases in Ethiopia, 01 January 2021 to 13 October 2024. World Health Organization.

Malaria is caused by parasitic unicellular Eukaryotes of the genus Plasmodium, and affects a wide range of terrestrial Vertebrates. Five different species of Plasmodium can cause Malaria in Humans, with most infections caused by either Plasmodium falciparum or Plasmodium vivax, both of which are endemic to Ethiopia. The parasites are primarily spread via the bite of the female Anopheles Mosquitoes (males do not bite), but can also be spread through blood transfusions, organ transplants, or practices such as needle-sharing.

Photomicrograph of a blood smear containing a macro- and microgametocyte of the Plasmodium falciparum parasite. Both macro- and microgametocytes are products of the erythrocytic life cycle. Within a few minutes after the Anopheles sp. vector ingests the gametocytes, microgametocytes develop into microgametes, which are able to fertilize gametes. Centers for Disease Control and Prevention/Wikipedia Commons.

Malaria manifests with approximately 10-15 days after infection, as a fever, headache, and chills. Mild cases often pass soon, and can be difficult to identify as Malaria, however, more severe cases can be fatal in as little as 24 hours after the onset of symptoms. 

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Saturday, 5 October 2024

Outbreak of Marburg Virus reported in Rwanda.

On 27 September 2024 the  Rwanda Ministry of Health confirmed that an outbreak of Marburg Virus Disease was present in the country, following the detection of the Virus in the blood of two patients by real-time reverse transcription polymerase chain reaction analysis at the National Reference Laboratory of the Rwanda Biomedical Center, according to a press release issued by the World Health Organization on 30 September 2024.

As of 29 September 2024, 26 cases of the disease have been reported in seven of the country's thirty districts (Gasabo, Gatsibo, Kamonyi, Kicukiro, Nyagatare, Nyarugenge and Rubavu), with eight people having died of the disease, a case fatality rate of 31%. The majority of the patients are healthcare workers from two health facilities in Kigali; this is not uncommon with outbreaks of the Marburg and Ebola viruses, with the highly transmittable nature of these diseases often resulting in aa high mortality rate in healthcare workers around the initial locus of the outbreak.

Contract tracing has led to the screening of about 300 contacts of diagnosed patients, one of whom had travelled to Belgium, with all found to be healthy and not a threat to public health. The initial source of the outbreak is still under investigation.

Marburg Virus Disease is a haemorrhagic fever, similar to the closely related Ebola Virus Disease. Both are caused by single-strand negative-sense RNA viruses of the Filoviridae family. Both are easily spread though contact with bodily fluids, and can also spread by contaminated clothing and bedding. 

Negative stained transmission electron micrograph of a number of filamentous Marburg Virions, which had been cultured on Vero cell cultures, and purified on sucrose, rate-zonal gradients. Erskine Palmer/Russell Regnery/Centers for Disease Control and Prevention/Wikimedia Commons.

Marburg Virus has an incubation period of between two and 21 days, manifesting at first as a high fever, combined with a severe headache and a strong sense of malaise. This is typically followed after about three days by severe abdominal pains, with watery diarrhoea and vomiting. In severe cases the disease develops to a haemorrhagic stage after five-to-seven days, manifesting as bleeding from some or all bodily orifices. This typically leads to death on day eight or nine, from severe blood loss and shock. There is currently no treatment or vaccine available for Marburg Virus, although a number of teams are working on trying to develop vaccines. 

Previous outbreaks of Marburg Virus have been reported in Rwanda, as well as the neighbouring Democratic Republic of Congo and Tanzania. The Virus has also been reported in a number of other African countries, including Angola, Equatorial Guinea, Ghana, Guinea, Kenya, and South Africa. The most recent outbreaks occurred in January 2023, with unrelated epidemics in Tanzania and Equatorial Guinea. 

The high rate of infection of healthcare workers seen in Marburg Virus is particularly alarming, as this tends to weaken communities ability to resist the Virus. The Virus can spread quickly in healthcare settings, infecting people whose immune systems are already stressed by other conditions, and creating aa reserve which can feed infections in the wider community. This makes it important to screen all people potentially infected with the disease as quickly as possible, and to arrange for patients to be treated in isolation, as well as quickly tracing all known contacts of any cases, and screening them for infection too.

Marburg Virus is a zoonotic infection (disease transferred from Animals to Humans), with a wild-reserve of the Virus known to be present in Egyptian Fruit Bats, Rousettus aegyptiacus, which are found across much of Africa, the Mediterranean region, the Middle East, and South Asia. These Bats form large colonies in caves or sometimes mines. They are frugivores, and can be major pests of farmed fruits, bringing them into conflict with Humans, and are sometimes hunted for food, all of which create potential avenues for the Marburg Virus to pass from a Bat host to a Human one.

A colony of Egyptian Rousette Bats, Rousettus aegyptiacus. Giovanni Mari/Flikr/iNaturalist.

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Tuesday, 3 September 2024

Outbreak of Chandipura Virus causes at least 82 deaths in India.

Between 1 June and 15 August 2024, the Indian Ministry of Health and Family Welfare recorded 245 cases of suspected Chandipura Virus infection in Gujarat and Rajasthan states, with 45 districts affected and 82 known deaths, a case fatality rate of 33%, according to a press release issued by the World Health Organization on 23 August 2024. Sixty four of the cases have been confirmed as Chandipura Virus by either immunoglobulin M enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction, sixty one of these in Gujarat and three in Rajasthan. The number of new cases being reported has been declining since 19 July 2024.

Chandipura Virus, or Chandipura vesiculovirus, is endemic to western, central, and southern India, with sporadic outbreaks occurring across this region,  typically during the monsoon season. In 2023 an outbreak of the Virus in Andhra Pradesh led to 183 deaths among 329 reported cases, a case fatality rate of 55.6%. Other recent outbreaks have led to case fatality rates of between 56 and 75%. In Gujarat there appears to be a spike in cases every four-to-five years. 

Chandipura vesiculovirus is a negative-sense single-stranded RNA Virus in the family Rhabdoviridae. Like many Viruses in this family, it is a zoonotic disease which can be spread by a number of Arthropod vectors, including Sandflies, Mosquitoes, and Ticks, although its main vector appears to be the Sandfly, Phlebotomus papatasi. Notably, although Human infections with Chandipura vesiculovirus have been reported only from India, the Sandfly, Phlebotomus papatasi, has a much wider distribution, and the Virus has been extracted from Sandflies in Senegal, as well as a range of Mammals in Senegal, Nigeria, Bhutan, and Nepal, suggesting a much wider, undetected, range.

Transmission electron micrographs of primary Chandipura Virus isolates from culture. Rao et al. (2004).

Chandipura Virus infection can lead to the development of a febrile disease, predominantly in children under 15, which can lead rapidly to convulsions, coma, and in the worst cases, death. In children, where fatality occurs, it typically happens within 48-72 hours of the first symptoms being detected.

The Indian Ministry of Health and Social Welfare has deployed specialist teams to Gujarat State to help implement control measures, including fumigating dwellings with insecticide to control the vectors of the disease and an education campaign aimed at raising awareness of the Virus, symptoms, and preventive measures.

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Wednesday, 24 July 2024

Local transmission of Dengue Fever recorded in Iran for the first time.

The transmission of Dengue Fever within Iran has been demonstrated for the first time in June 2024, according to a press release issued by the World Health Organization on 22 July 2024. The Ministry of Health and Medical Education of Iran reported to cases of the disease had been confirmed by Polymerase Chain Reaction testing at the Pasteur Institute in Bandar Abbas, both in patients from the city of Bandar-Lengheh in Hormozgan Province who had never travelled outside of Iran, and who can therefore be confirmed to have acquired the infection within the country. By 17 July 2024 twelve cases had been confirmed in Bandar-Lengheh among people who had no history of travel outside the country.

This development is not entirely unexpected, as the number of imported cases within Iran has remained steady at about 20 per year between 2017 and 2023, and the Aedes aegypti and Aedes albopictus Mosquitoes, which act as vectors for the disease, are both present in Sistan and Balouchistan, Hormozgan, Bushehr, Khuzastan, and Gilan provinces. In 2024 the number of cases in the country has risen sharply, with 137 reported between 15 May and 10 July.

Dengue is a viral infection transmitted to humans through the bite of infected Mosquitoes and is found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas. The primary vectors that transmit the disease are Aedes aegypti Mosquitoes and, to a lesser extent, Aedes albopictus.  These mosquitoes are also vectors of Chikungunya, Yellow Fever and Zika viruses. Dengue is widespread throughout the tropics, with local variations in risk influenced by climate parameters as well as social and environmental factors.

Colour print of the Dengue Mosquito Aedes aegypti (then called Stegomyia fasciata, today also Stegomyia aegypti). To the left, the male, in the middle and on the right, the female. Above left, a flying pair in copula. Emil August Goeldi (1905)/Wikimedia Commons.

Infection with the Dengue Virus can cause a wide spectrum of disease. Ranging from subclinical disease (people may not know they are even infected) to severe flu-like symptoms in those infected. Although less common, some people develop Severe Dengue, which can be any number of complications associated with severe bleeding, organ impairment and/or plasma leakage. Severe Dengue has a higher risk of death when not managed appropriately. Severe Dengue was first recognised in the 1950s during Dengue epidemics in the Philippines and Thailand. Today, Severe Dengue affects most Asian and Latin American countries and has become a leading cause of hospitalisation and death among children and adults in these regions.

Dengue is caused by a Virus of the Flaviviridae family of positive-strand RNA Viruses and there are four distinct, but closely related, serotypes of the Virus that cause Dengue (Dengue Fever Virus-1, Dengue Fever Virus-2, Dengue Fever Virus-3 and Dengue Fever Virus-4). Recovery from infection is believed to provide lifelong immunity against that serotype. However, cross-immunity to the other serotypes after recovery is only partial, and temporary. Subsequent infections (secondary infection) by other serotypes increase the risk of developing Severe Dengue.

A transmission electron micrograph showing Dengue Virus virions (the cluster of dark dots near the centre). Centers for Disease Control and Prevention/Wikimedia Commons.

Dengue has distinct epidemiological patterns, associated with the four serotypes of the Virus. These can co-circulate within a region, and indeed many countries are hyper-endemic for all four serotypes. Dengue has an alarming impact on both human health and the global and national economies. Dengue Fever Virus is frequently transported from one place to another by infected travellers; when susceptible vectors are present in these new areas, there is the potential for local transmission to be established.

The incidence of Dengue has grown dramatically around the world in recent decades. A vast majority of cases are asymptomatic or mild and self-managed, and hence the actual numbers of dengue cases are under-reported. Many cases are also misdiagnosed as other febrile illnesses.

One modelling estimate indicates 390 million Dengue Virus infections per year, of which 96 million manifest clinically (with any severity of disease). Another study on the prevalence of dengue estimates that 3.9 billion people are at risk of infection with dengue viruses. Despite a risk of infection existing in 129 countries, 70% of the actual burden is in Asia.

The number of dengue cases reported to the World Health Organization increased over 8 fold over the last two decades, from 505 430 cases in 2000, to over 2.4 million in 2010, and 5.2 million in 2019. Reported deaths between the year 2000 and 2015 increased from 960 to 4032, affecting mostly younger age group. The total number of cases seemingly decreased during years 2020 and 2021, as well as for reported deaths. However, the COVID-19 pandemic might have also hampered case reporting in several countries.

The overall alarming increase in case numbers over the last two decades is partly explained by a change in national practices to record and report Dengue to the Ministries of Health, and to the World Health Organization. But it also represents government recognition of the burden, and therefore the pertinence to report Dengue disease burden.

Before 1970, only 9 countries had experienced Severe Dengue epidemics. The disease is now endemic in more than 100 countries in the World Health Organization regions of Africa, the Americas, the Eastern Mediterranean, South-East Asia and the Western Pacific. The Americas, South-East Asia and Western Pacific regions are the most seriously affected, with Asia representing about 70% of the global burden of disease.

Not only is the number of cases increasing as the disease spreads to new areas including Europe, but explosive outbreaks are occurring. The threat of a possible outbreak of Dengue now exists in Europe; local transmission was reported for the first time in France and Croatia in 2010 and imported cases were detected in 3 other European countries. In 2012, an outbreak of Dengue on the Madeira islands of Portugal resulted in over 2000 cases and imported cases were detected in mainland Portugal and 10 other countries in Europe. Autochthonous cases are now observed on an annual basis in few European countries.

Iran forms part of the World Health Organization's Eastern Mediterranean Region, which is considered to be at high risk to Dengue Fever epidemics, with many countries having fragile healthcare systems due to conflict and political instability, while other countries where healthcare systems are considered to be stronger are sufferering increased rains due to climate change, leading to a proliferation of the Aedes aegypti and Aedes albopictus Mosquitoes which act as vectors for the disease. 

The countries of the World Health Organization's Eastern Mediterranean Region. Ã–zturk et al. (2024).

Iran is particularly threatened by the presence of both types of Mosquito and a climate favourable to the spread of the disease, as well as a large numbers of visitors from countries where the disease is endemic. The discovery that the disease is being transmitted in the country at this time is particularly alarming as it comes shortly before the annual Arba'in Pilgrimage, which this year will take place in August, with potentially millions of Shiite Muslims from around the world visiting the Shrine of Husayn ibn Ali in the city of Karbala in central Iran.

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