Subject: Biotech and Medical Sciences

With cases of tomato flu reported from at least four states — Kerala, Tamil Nadu, Haryana, and Odisha — the Union Health Ministry has issued a set of guidelines on prevention, testing, and treatment of the infection.

Researchers believe that it is a different clinical presentation of hand-foot-and mouth disease (HFMD) caused by a group of enteroviruses (viruses transmitted through the intestine).

What is Tomato Flu?

• Tomato flu or tomato fever is characterized by fever, joint pain, and red, tomato-like rashes usually seen in children below the age of five years.
• This is accompanied by other symptoms of viral fevers such as diarrhoea, dehydration, nausea and vomiting, and fatigue.
• This was thought to be an aftereffect of dengue and chikungunya that is commonly seen in Kerala.
• However, researchers now believe that it is HFMD caused by enteroviruses like Coxsackievirus A-6 and A-16.

Is it very uncommon?

• Tomato flu could be an after-effect of chikungunya or dengue fever in children rather than a viral infection.
• It could also be a new variant of the viral hand, foot, and mouth disease, a common infectious disease targeting mostly children aged 1–5 years and immunocompromised adults.
• HFMD is not a new infection, we have read about it in our textbooks. It is reported from time to time across the country, but it is not very common.

Why is the infection spreading now?

• There actually are more cases or because we are more vigilant about viral infections and testing after Covid-19.
• Since the disease is self-limiting, doctors do not usually test for it.
• There are so many viral infections in children, but we cannot — and there is no need to — test for each and every one of it.

Which pathogen is causing it now? And how is the clinical presentation different?

• The current HFMD cases are mainly caused by Coxsackievirus A-6 and A-16.
• Another pathogen — Enterovirus71 — that also causes the disease is not very prevalent now, according to her.
• This is good because the pathogen was known to lead to severe neurologic symptoms, including fatal encephalitis (brain inflammation).
• In almost all cases, say 99.9% cases, the disease is self-limiting.
• But, in a small number of cases it can lead to CNS (central nervous system) complications.

Is there a treatment for the infection?

• There is no specific treatment or vaccine available for the disease.
• Those with the infection are treated symptomatically, such as prescription of paracetamol for fever.

How can the infection be prevented?

• As it happens mainly in children, the Centre’s advisory focuses on preventions in these age groups.
• As per the advisory, anyone suspected to have the infection should remain in isolation for five to seven days after the onset of the symptoms.
• It states that children must be educated about the infection and asked not to hug or touch other children with fever or rashes.
• The children should be encouraged to maintain hygiene, stop thumb or finger sucking, and use a handkerchief for a running nose, the advisory states.

UPSC 2023 countdown has begun! Get your personal guidance plan now! (Click here)

Researchers from across the world have made available over 650 complete genome sequences of monkeypox isolates to date in public domain databases including GISAID and GenBank.

What is Genome Sequencing?

• Genome sequence is the unique code of genetic material of any organism, and determines the characteristic of any organism.
• Whole genome sequencing is the process of determining the complete DNA sequence of an organism’s genome at a single time.
• The gene composition of novel coronavirus, for instance, is different from that of the influenza virus. Every organism has a unique genome sequence.
• Laboratories in various countries have been isolating and sharing the genome sequences of the virus on an international platform.

Why are so many genome sequences being isolated?

• When viruses multiply, or reproduce, there is a copying mechanism that transfers the gene information to the next generation.
• However, no copying mechanism is perfect. When the virus multiplies, there will be small changes, which are called mutations.
• These mutations accumulate over time, and after prolonged periods, are responsible for evolution into new organisms.
• Within a single reproduction, the changes are extremely minor. More than 95 per cent of the gene structure remains the same.

How does it help scientists?

• However, the small changes that occur are crucial to understanding the nature and behaviour of the organism.
• In this case, for example, the small changes could provide scientists with information about the origin, transmission, and impact of the virus on the patient.
• It could also hold clues to the differing effects the virus could have on patients with different health parameters.

Accelerated evolution of Monkeypox

• The monkeypox virus has a DNA genome of around 2,00,000 base pairs, roughly six times larger than that of SARS-CoV-2.
• Like other viruses, the monkeypox virus evolves by the accumulation of genetic errors, or mutations, in its genome when it replicates inside a host.
• Being a DNA virus, the monkeypox virus like other poxviruses was believed to have a small rate of accumulating genetic changes compared to viruses with an RNA genome like SARS-CoV-2, which have a much larger rate of mutations.
• For poxviruses, this rate is estimated to be as low as a couple of genetic changes every year.
• A recent study, however, revealed that the observed rate of genetic changes in the virus was higher than expected — average of around 50 genetic changes.

Key findings

Ans. APOBEC3 protein

• The study also suggests that several mutations that have been identified in the new sequences of the monkeypox virus.
• This may have emerged due to interaction between the virus genome and an important family of proteins coded by the human genome known as the Apolipoprotein B Editing Complex (or APOBEC3).
• These proteins offer protection against certain viral infections by editing the genome sequence of the virus while it replicates in the cell.
• Some researchers suggest that many of the genetic mutations in the monkeypox genomes from the current outbreak are relics of the effect of APOBEC3.

Conclusion

• Genomic surveillance of pathogens provides interesting insights by following a molecular approach for contact tracing and understanding the transmission of the virus across the world.
• As cases of monkeypox continue to rise, it is therefore important to strengthen the genomic surveillance for the monkeypox virus.
• Since data from the present outbreak suggest a sustained human-to-human transmission, continuous genomic surveillance is important to understand the evolution and adaptation of the virus, apart from providing useful data to epidemiologists.
• With COVID-19 continuing unabated and monkeypox around the corner, the time has never been better, and the need never more acute, to build a sustainable system for genomic surveillance in India.

UPSC 2023 countdown has begun! Get your personal guidance plan now! (Click here)

The bacteria causing typhoid fever is becoming increasingly resistant to some of the most important antibiotics for human health.

What is the news?

• The largest genome analysis of Salmonella Typhi (S. Typhi) also shows that resistant strains — almost all originating in South Asia — have spread to other countries nearly 200 times since 1990.
• The researchers noted that typhoid fever is a global public health concern, causing 11 million infections and more than 1,00,000 deaths per year.
• Antibiotics can be used to successfully treat typhoid fever infections, but their effectiveness is threatened by the emergence of resistant S. Typhi strains.

What is Salmonella Typhi?

• Salmonella Typhi (S. Typhi) are bacteria that infect the intestinal tract and the blood.
• It is usually spread through contaminated food or water.
• Once S. Typhi bacteria are eaten or drunk, they multiply and spread into the bloodstream.
• The disease is referred to as typhoid fever. S. Paratyphi bacteria cause a similar, but milder illness, which comes under the same title.
• Paratyphoid has a shorter duration, generally, than typhoid.
• Typhi and S. Paratyphi are common in many developing countries where sewage and water treatment systems are poor.

How does it spread?

• Salmonella Typhi lives only in humans.
• Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract.
• Symptoms include prolonged high fever, fatigue, headache, nausea, abdominal pain, and constipation or diarrhoea.
• Some patients may have a rash. Severe cases may lead to serious complications or even death.
• Typhoid fever can be confirmed through blood testing.

UPSC 2023 countdown has begun! Get your personal guidance plan now! (Click here)

A trial on 18 colorectal cancer patients in the US found that cancer could be treated without chemotherapy or surgery. The world is sitting up and taking note of Dostarlimab, which has been called a wonder drug.

What is Dostarlimab?

• Dostarlimab is an experimental drug. It contains laboratory-produced molecules.
• It acts as substitute antibodies. It is sold under the brand name Jemperli.
• It was approved for medical use in the United States and the European Union in 2021.
• Its side-effects include vomiting, joint pain, itching, rash, fever etc.

What are the findings?

• The trial showed that immunotherapy alone – without any chemotherapy, radiotherapy, or surgery that have been staples of cancer treatment.
• It could completely cure the patients with a particular kind of rectal cancer called ‘mismatch repair deficient’ cancer”.
• All 12 patients had completed the treatment and were followed for six to 25 months after.
• No cases of progression or recurrence had been reported during the follow-up.
• The response too was rapid, with symptoms resolving in 81% of the patients within nine weeks of starting the therapy.

Is Dostarlimab actually very effective?

• Dostarlimab is not a new drug but a combination of drugs that are already approved for use in immunotherapy.
• There is a possibility that Dostarlimab may improve the outcome and survival rate in rectal cancer patients but to say it as a magic drug for cancer is completely going overboard.

How does this drug cure?

• PD1 is a protein that regulates immune function and can sometimes keep T cells from killing cancer cells.
• The therapy in the trial used PD1 blockades, allowing T cells to kill cancer cells.
• ‘Mismatch repair deficient’ cancer is most common among colorectal, gastrointestinal, and endometrial cancers.
• Patients suffering from this condition lack the genes to correct typos in the DNA that occur naturally while cells make copies.
• Immunotherapy belongs to a category called PD1 blockades that are now recommended for the treatment of such cancers rather than chemotherapy or radiotherapy.

Will Indian patients get access to the drug?

• At present, Indian doctors seem to be generally wary of prescribing Dostarlimab for their patients.
• Experts have termed as optimistic the findings of an ongoing trial—a group of rectal cancer patients showed no signs of a tumour after taking the drug for six months.
• None of the participants reported any severe side-effects either.
• Yet, doctors say they want to assess the duration of the response.

What do we know about the clinical trial?

• Cancer was treated in all the patients and could not be detected by physical examination, endoscopy, positron emission tomography, or magnetic resonance imaging.
• Thus, there is a thought that cancer can be treated without chemotherapy or surgery.

Is it too early to celebrate?

• Cancer specialists said initial signals show how precision medicine is building the future but they need to test more patients from different areas and other types of cancers.
• The combination of drugs was administered to a small number of patients and for a specific type of cancer.

UPSC 2023 countdown has begun! Get your personal guidance plan now! (Click here)

The Kerala health department is on alert after the death occurred due to the West Nile Virus.

West Nile Virus

• The West Nile Virus is a mosquito-borne, single-stranded RNA virus.
• According to the WHO, it is a member of the flavivirus genus and belongs to the Japanese Encephalitis antigenic complex of the family Flaviviridae.

How does it spread?

• Culex species of mosquitoes act as the principal vectors for transmission.
• It is transmitted by infected mosquitoes between and among humans and animals, including birds, which are the reservoir host of the virus.
• Mosquitoes become infected when they feed on infected birds, which circulate the virus in their blood for a few days.
• The virus eventually gets into the mosquito’s salivary glands.
• During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness.
• WNV can also spread through blood transfusion, from an infected mother to her child, or through exposure to the virus in laboratories.
• It is not known to spread by contact with infected humans or animals.

Symptoms of WNV infection

• The disease is asymptomatic in 80% of the infected people.
• The rest develop what is called the West Nile fever or severe West Nile disease.
• In these 20% cases, the symptoms include fever, headache, fatigue, body aches, nausea, rash, and swollen glands.
• Severe infection can lead to encephalitis, meningitis, paralysis, and even death.
• It is estimated that approximately 1 in 150 persons infected with the West Nile Virus will develop a more severe form of the disease.
• Recovery from severe illness might take several weeks or months.
• It usually turns fatal in persons with co-morbidities and immuno-compromised persons (such as transplant patients).

UPSC 2023 countdown has begun! Get your personal guidance plan now! (Click here)