Cancer is a large group of diseases that can start in almost any organ or tissue of the body when abnormal cells grow uncontrollably, and go beyond their usual boundaries to invade adjoining parts of the body. According to the World Health Organization (WHO), it is the second most common cause of death globally, accounting for millions of deaths every year. Lung, prostate, colorectal, stomach and liver cancer are the most common types of cancer in men, while breast, colorectal, lung, cervical and thyroid cancer are the most common among women. However, these are not necessarily the deadliest forms of cancer.

What makes cancer the deadliest depends upon how many people have it and what percentage of those people actually survive. Cancer researchers determine this on the basis of five-year relative survival. This is the percentage of people who are expected to survive the effects of a given cancer, excluding their risk of other possible causes of death, for five years past a diagnosis. It is also important to note that what makes cancer really deadly is that practically no cure for it. A cure for cancer would imply that there are no cancerous cells remaining in the body.

Here are the 5 deadliest cancers in the U.S., according to SEER five-year relative survival data for cases diagnosed between 2014 and 2020.

1. Pancreatic cancer occurs when cells in your pancreas, a gland in your abdomen that aids digestion, mutate and multiply out of control, forming a tumour. Major risk factors include smoking, obesity, diabetes, chronic pancreatitis, certain genetic mutations and environmental chemical exposure.

2. Esophageal cancer develops in the oesophagus, which is the tube that connects your throat to your stomach.

3. Liver cancer and intrahepatic bile duct cancer originate in the liver or bile ducts, often linked to hepatitis infections, heavy alcohol use, obesity, and aflatoxin exposure.

4. Lung and bronchus cancer primarily caused by smoking, secondhand smoke, and environmental pollutants, affects the lungs and airways, making it the leading cause of cancer death in the US.

5. Acute myeloid leukaemia (AML) is an aggressive blood and bone marrow cancer that progresses rapidly, often linked to genetic mutations, radiation exposure, and certain chemicals.

ALSO READ: Why Are Lifestyle Factors Making Millennials Vulnerable To Cancer?

The situation regarding the outbreak of Ebola is nowhere near slowing down, and the World Health Organization (WHO) said that this outbreak of Ebola is far from under control. The outbreak of the disease in eastern Democratic Republic of the Congo (DRC) and neighboring Uganda has already reached the 500 mark.

On Saturday, the Democratic Republic of the Congo (DRC) reported that its total number of Ebola cases had increased to 488 from 452 cases and caused 86 deaths. Its neighbor, Uganda, also has reported 19 cases.

This time the Ebola outbreak has caused most harm to the Democratic Republic of the Congo (DRC) and during this mayhem its neighboring nation Uganda which is also fighting to contain the disease as it is also seeing surge in cases thus it has completely closed off its western border with DRC.

The worsening condition of the situation is clear, as the global health monitoring organization, the World Health Organization (WHO), has already declared the outbreak an international public health emergency.

And it's not only the case with WHO, another big name in public health, but the United States' Centers for Disease Control and Prevention (CDC) warned that the Ebola outbreak of this time could swell to become the largest Ebola epidemic to date, and is likely to rival the 2014-2016 epidemic in West Africa.

The patient number is still growing as the disease is spreading, and this spread is very hard to contain without an approved vaccine. Though work on the vaccine is in full swing, research on three different vaccines for the Bundibugyo strain of Ebola still needs time, even after being set to be fast-tracked for trials.

What Is Ebola?

Ebola is a severe and deadly disease caused by a virus mostly found in Africa. The spread of the disease happens through contact with infected body fluids.

Some symptoms can indicate a possible infection. This includes fever, headache, weakness, vomiting, diarrhea, muscle pain, sore throat, and unexplained bleeding. This eventually leads to severe complications like bleeding, organ failure, and death.

Ebola is a highly lethal viral hemorrhagic fever first identified in 1976. Over the past five decades, it has caused over 30 outbreaks, primarily in Central and West Africa. The virus takes its name from the Ebola River in the Democratic Republic of the Congo (DRC).

Three strains of the virus — Ebola virus, Sudan virus, and Bundibugyo virus — have caused the largest outbreaks in Africa. Among them, the Ebola virus is considered the deadliest, with fatality rates reaching up to 90% without treatment.

These viruses have repeatedly emerged from animal reservoirs and infected humans in African countries. In the Democratic Republic of the Congo alone, this marks the 17th Ebola outbreak and the third linked to the Bundibugyo strain.

After Rajasthan and Hyderabad, Chhattisgarh today reported three suspected cases of Ebola involving foreign nationals.

According to media reports, the three have been isolated in Durg and placed under a 21-day quarantine as a precaution.

Chhattisgarh Health Minister Shyam Bihari Jaiswal announced that the state is fully prepared to handle any potential Ebola virus infection, stressing that hospitals and quarantine facilities have been put on alert and necessary arrangements are in place to ensure public safety.

Speaking to reporters, Jaiswal said the three individuals under observation were nationals from African countries and were being monitored in line with health protocols.

He added that no Ebola infection had been confirmed so far and that none of the individuals were showing symptoms of the disease.

"We have been fully prepared across the state at every level for a month now. The three individuals placed in isolation in Durg are nationals from African countries and have been quarantined for 21 days as a precautionary measure. So far, tests have not confirmed the presence of the virus, nor are they exhibiting any symptoms," he said.

Two Suspected Cases In Hyderabad

Earlier, two people in Hyderabad who returned from Sudan were isolated.

A Sudanese national, a student in his 20s, with a fever, was admitted to the state-run Gandhi Hospital. The student's condition improved, and he had no fever on Friday morning. His attendant was advised to stay in isolation at home, according to media reports.

Also read: WHO Says Ebola Fight Is Catching Up; Expert Explains Science Behind Patient Recoveries

Another Sudanese national, who arrived at Rajiv Gandhi International Airport a day earlier, was also shifted to the isolation ward of Gandhi Hospital for further tests after he was found to have a fever during thermal screening at the airport. The 35-year-old, who had come to Hyderabad for knee surgery, had no fever as of Friday morning and was asymptomatic, officials said.

Samples containing oral and nasal swabs have been collected and will be sent to the Centre for Cellular and Molecular Biology (CCMB) for testing. Though two patients have now tested negative.

Rajasthan Woman Isolated

Meanwhile, Rajasthan has also isolated one woman who returned from Uganda following symptoms.

During routine health screening at the airport, she exhibited symptoms associated with Ebola infection. The health department was immediately informed, and she was placed under special observation.

While she has displayed symptoms similar to Ebola infection, confirmation can only be made after laboratory testing. The results are awaited.

No Ebola Case Reported In India

Read More: Bundibugyo Ebola Outbreak: WHO Identifies Experimental Treatments, Vaccines

All suspected cases have been linked to travel to Ebola-affected countries such as Uganda, the Democratic Republic of Congo, and Sudan.

"No Ebola disease cases have been reported in India," the Health Ministry said in its latest update on June 3. The Health Ministry has also advised travelers arriving from Ebola-affected countries, including Uganda and the Democratic Republic of Congo, to remain alert for symptoms and seek medical guidance if they feel unwell.

"For information, guidance, and assistance, call MoHFW's 24x7 Health Helpline: 1075," the ministry said on X.

Ebola: A Global Health Emergency

On May 17, the World Health Organization classified the Ebola outbreaks in Uganda and the Democratic Republic of Congo as a Public Health Emergency of International Concern (PHEIC).

A total of 452 Ebola cases have been confirmed in the Democratic Republic of Congo, including 82 deaths. Uganda has reported 16 confirmed cases.

Meanwhile, the number of suspected cases has fallen from more than 1,000 last week to 116 as health teams work through the backlog. Six people in the DRC and two in Uganda have recovered to date.

After previously warning that Ebola was "outpacing us," WHO Director-General Tedros Adhanom Ghebreyesus said on Thursday that "we are catching up" as efforts to contain the outbreak in the Democratic Republic of Congo show progress.

A total of 452 Ebola cases have been confirmed in the Democratic Republic of Congo, including 82 deaths. Uganda has reported 16 confirmed cases. Meanwhile, the number of suspected cases has fallen from more than 1,000 last week to 116 as health teams work through the backlog.

WHO Sees Signs of Progress

“What I saw gave me hope,” Ghebreyesus said at a press conference.

“The outbreak had a big head start, and we're still behind, but under the leadership of the Government of DRC, we are catching up,” he added.

Importantly, he noted that six people in the DRC and two in Uganda have recovered to date, “showing that people can survive Ebola if they have access to care and go to health facilities as soon as they show symptoms.”

Why Are Patients Recovering?

The latest outbreak is caused by the Bundibugyo strain of the Ebola virus, for which there is currently neither a vaccine nor an antiviral treatment. So how are patients recovering?

Dr. Rajeev Jayadevan, Co-Chairman of the National IMA COVID Task Force and Past President of the Indian Medical Association, Cochin, told HealthandMe that a combination of factors—including the virus strain, access to medical care, and individual immune responses—can significantly influence whether a patient survives the disease.

Ebola virus disease is a severe illness caused by different strains of the Ebola virus. The current outbreak is linked to the Bundibugyo strain, which has a lower mortality rate than the more lethal Zaire strain responsible for several previous outbreaks, he said.

“The mortality of Ebola virus disease is tied to several components,” Dr. Rajeev explained.

Early Medical Care Improves Survival

One of the most important factors is access to early medical attention and supportive care. Patients who receive prompt treatment at well-equipped healthcare facilities staffed by experienced healthcare workers have a much greater chance of survival.

However, such healthcare access is often limited in outbreak-affected regions of Africa due to ongoing conflicts and socioeconomic challenges.

“The chance of survival is much higher if a person receives good medical attention and early supportive care,” he said.

Bundibugyo Strain vs Zaire Strain

Also read: Ebola Bundibugyo Strain: All You Should Know About The Rare Virus

The strain of the virus also plays a critical role. Dr. Rajeev said that because the Bundibugyo strain is less lethal than the Zaire strain, more infected individuals are expected to survive under similar conditions.

“If a hundred people get infected with the Zaire strain and another hundred with the Bundibugyo strain, more people in the Bundibugyo group will survive, all other conditions remaining the same,” he said.

Difference In Immune Response

Another important factor is the body's immune response, which varies from person to person. Dr. Rajeev highlighted the role of human leukocyte antigens (HLA), proteins that help the immune system recognize and respond to invading pathogens. Because each individual's HLA profile is unique, people infected with the same virus can generate different immune responses.

“HLA works closely with the immune system by presenting pieces of the virus to immune cells, helping the body build a targeted response,” he said.

Also read: Ebola Alert In India: Rajasthan, Hyderabad Report Suspected Cases of Deadly Virus

This biological diversity is one reason why the same infection can affect individuals differently. It is also considered an evolutionary safeguard that helps prevent a single pathogen from devastating the entire human population.

The Role of Probability

Dr. Rajeev also pointed to a simple statistical reality. “If the mortality rate in the current outbreak is around 30 per cent, that means about 70 per cent of infected individuals are expected to survive,” he said.

According to the expert, survival often results from a combination of favorable factors, including infection with a less lethal strain, timely medical care, a strong immune response, and the overall probability of recovery within a given outbreak.