What Matters in Global Health #111

A new paper in?Genome Biology and Evolution,?published by Oxford University Press, shows that rapid evolution in bats may account for the animals’ extraordinary ability to host and survive infections and avoid cancer.?https://www.eurekalert.org/news-releases/1001498#

Bats are exceptional among mammals for their ability to fly, long lives, low cancer rates, and robust immune systems. Bats are also thought to have played a role in the emergence of SARS-CoV-2. The ability of bats to tolerate viral infections may stem from unusual features of their innate immune response.

These characteristics make bats an interesting animal to investigate because they may affect human health. For example, by better understanding the mechanisms of the bat immune system that allow bats to tolerate viral infections, researchers may be better able to prevent disease outbreaks from animals to people. Comparative genomic analyses of bats and cancer-susceptible mammals may eventually provide new information on the causes of cancer and the links between cancer and immunity. Studies of bats and other organisms complement studies based on mouse models; mice are more amenable than bats to experimental manipulation but exhibit fewer characteristics with implications for human disease.

Here, researchers using the Oxford Nanopore Technologies long-read platform and bat samples collected with help from the American Museum of Natural History in?Belize sequenced the genomes of two bat species, the Jamaican fruit bat and the Mesoamerican moustached bat, and carried out a comprehensive comparative genomic analysis with a diverse collection of bats and other mammals.

The researchers found genetic adaptations in six DNA repair-related proteins and 46 proteins in bats that were cancer-related, meaning that researchers have previously found such proteins suppress cancer. Notably, the study found that these altered cancer-related genes were enriched more than two-fold in the bat group compared to other mammals.

“By generating these new bat genomes and comparing them to other mammals we continue to find extraordinary new adaptations in antiviral and anticancer genes,” said the paper’s lead author, Armin Scheben. “These investigations are the first step towards translating research on the unique biology of bats into insights relevant to understanding and treating ageing and diseases, such as cancer, in humans.”

The paper, “Long-read sequencing reveals rapid evolution of immunity and cancer-related genes in bats,” is?available at:?https://academic.oup.com/gbe/article/15/9/evad148/7259420.

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Nigeria logged nearly 6,000 cases of diphtheria in July and August, more than were reported globally in 2022, the World Health Organization (WHO) announced last week. www.science.org/content/article/news-glance-diphtheria-vaccine-shortage-prisoner-release-and-inaturalist-s-growth?

Respiratory droplets and direct contact spread the bacterial disease and can be prevented by a vaccine. It has a case fatality rate of as high as 40% if not treated with antitoxin—supplies of which are “very constrained,” WHO reported. The organisation says it has shipped 4500 of the 14,200 vials that Nigeria has requested. Algeria, Guinea, and Niger have reported smaller outbreaks recently. WHO says Guinea and four other countries and Nigeria have separately requested 4000 vials. WHO purchases antitoxin, made in horses, from just two companies, and supply has been problematic for a decade. Almost all of Nigeria’s infections were in the country’s politically unstable north. Nearly 75% occurred in children younger than 15, just 23% of whom were fully vaccinated.

The southern Indian state of Kerala is now battling another deadly outbreak of the Nipah virus, its fourth since 2018. Authorities were alerted to the outbreak after two deaths attributed to the virus. www.npr.org/sections/goatsandsoda/2023/09/15/1199886718/another-nipah-outbreak-in-india-what-do-we-know-about-this-virus-and-how-to-stop?

A 49-year-old man, Mohammed Ali, who lived in the village of Maruthonkara, died on August 30, and 40-year-old Mangalatt Haris, who lived in the town of Ayanchery, died on September 11.

On September 13, test results confirmed that both men had died of Nipah. Authorities tested for the virus from routine nose swabs. A combination of flu-like and neurological symptoms — headache, fever, cough, acute respiratory distress and seizures — alerted them to test for the virus.

The virus, first identified among pig farmers in Malaysia in 1999, likely jumped to humans at that time from infected pigs. But there was no human-human transmission noted during the Malaysian outbreaks, says Dr. Thekkumkar Surendran Anish, associate professor for community medicine at the Government Medical College at Manjeri, Kerala, who is leading the state's surveillance team and who spoke to NPR about the situation.

There are two strains of the virus.

"There is virological evidence that the strain we're encountering in Kerala is the Bangladeshi strain," says Anish. This has a high fatality rate of 75% and causes acute respiratory distress, with the higher possibility of human-to-human transmission, he adds.

Meanwhile, health authorities wanted to determine if the cases were related. The one apparent connection, discovered on closed circuit TV footage, is that Haris was visiting a sick relative in a ward in the hospital where Ali was a patient — and the same health worker was identified in both wards. The virus is not airborne but can be spread with contact with body fluids from an infected person or with infected food.

The health worker was not wearing a mask or gloves. "It's possible that he could have transmitted the disease through contact with surfaces such as counters or the side of the bed," Anish says.

On the morning of September 15, Anish encountered yet another case — a 39-year-old man who'd been attending to a patient in the adjacent bed when Mohammed Ali was hospitalized. So far, in addition to the two deaths, Kerala has confirmed six active cases of Nipah.

Kerala has a wide variety of bat species; tests of some fruit bats in 2018 showed that they?harbored the virus. Samples of bat urine and half-eaten fruit?have now been collected?from Maruthonkara, the village in Kozhikode, where the first victim lived, and authorities are testing bats in the area for the virus too.

Health authorities in Kozhikode have created?43 containment zones, especially monitoring anyone with a fever as well as the 950 people who were in contact with the two deceased men. The state's?Health Minister Veena George advised the general public to wear masks as a precaution.

"There's no rationale for masking up, since the Nipah virus does not spread through the air," says epidemiologist Raman Kutty, research director at the Amala Cancer Institute in Thrissur, Kerala. "Health authorities are just being very cautious," he says.

They've also asked the public to be vigilant for such symptoms as headache, disorientation, fever, cough and seizures.

There is no vaccine nor cure for Nipah yet, and supportive care is all that patients can be given.

"The virus has an incubation period of 14-21 days," says Anish. "Judging from the time of the secondary infections, we're still in the middle of this outbreak," he says. And there's at least one piece of the puzzle that authorities still don't know — how the patient Ali contracted Nipah in the first place.

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US President Joe Biden’s 1-year-old agency to fund high-risk biomedical research is taking a starring role in his reignited Cancer Moonshot, an effort to halve the US cancer death rate by 2047. The White House said last week that the $1.5 billion Advanced Research Projects Agency for Health will spend an additional $240 million of its budget this year on moonshot-related projects, including surgery improvements, tools to detect tumours early, and bacterial treatments.

A second large clinical trial has shown that the psychedelic drug MDMA, also known as ecstasy or molly, effectively treats post-traumatic stress disorder (PTSD) when used in combination with psychotherapy. The trial’s success?brings the drug one step closer to approval by the US Food and Drug Administration, which typically requires two placebo-controlled trials. In the first trial, nearly 70% of people who received MDMA alongside therapy lost their PTSD diagnosis compared with 32% of those who received therapy and a placebo. The results of the second trial were similar and the drug seemed to work well in people with other mental illnesses such as depression, and across racial and ethnic groups.

Nature | 6 min References:?Nature Medicine?paper 1?&?Nature Medicine?paper 2

The rollout of Cervavac, India’s domestically manufactured vaccine against human papillomavirus (HPV),?has stalled. “It should definitely have been rolled out by now,” says public health researcher Kaushik Bharati. “I’m a bit disappointed.” Cervical cancer kills more than 77,000 Indian women each year, and these deaths could be largely prevented through HPV vaccination. Vaccine hesitancy in India is generally low, but a failed HPV vaccine trial in 2009 cast a pall over the rollout. And the link between HPV and sexual activity clashes with cultural taboos. Undark | 13 min read

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