Tuesday November 20, 2018

Study: Fever, chills, And Muscle Pain Could Be Signs Of Leptospirosis

Fever, chills, and muscle pain aren’t the symptoms just of malaria

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A herdsman walks his cattle as they graze in Naivasha, Kenya, Feb. 15, 2018.
A herdsman walks his cattle as they graze in Naivasha, Kenya, Feb. 15, 2018. VOA
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Fever, chills, and muscle pain aren’t the symptoms just of malaria. They could be signs of leptospirosis, which infects millions of people each year — primarily in tropical regions.

The under-reported disease is usually spread though contact with rodents, but a new study finds this trend may not hold in northern Tanzania or beyond.

Research in Asia has tied living in close quarters with rats to outbreaks of leptospirosis. The bacterial infection causes symptoms that are often mistaken for malaria. Severe cases can be life-threatening, says Professor Albert Ko at the Yale School of Public Health.

“Our group has done global burden of disease studies on this and there are over a million a cases a year and roughly 60 thousand deaths,” said Ko.

Common source of fevers

Leptospirosis is becoming recognized as a common source of fevers in Africa. But the source of the disease was unclear. It could be rats, or it could be something else, said Michael Maze, of the University of Otago.

“Well, we know that leptospirosis has many possible animal hosts,” said Maze. “I guess the story starts when we identified how common leptospirosis was the cause of severe fever in people coming to the hospital in northern Tanzania.”

Maze and an international team of researchers asked those patients about their lifestyles: how many rats they saw around their home… whether they owned livestock and if so, what kind?

They also tested blood samples for leptospirosis infections. Of the nearly 900 people tested, almost a third were infected, or had been.

The researchers also trapped almost 400 rats in nearby villages. They tested the rodents to see if they carried the leptospira bacterium like their Asian cousins. They did not.

But cattle did — they found over seven percent of them carried up to four types of leptospira that could potentially infect humans. Goats and sheep did, too, though less often.

cow
cow, Pixabay

Blood samples match

This result matched the findings from the patients’ blood samples. People who owned livestock were most likely to have leptospirosis infections, especially cattle owners.

“Leptospirosis is carried in the renal tract — so the kidney and the bladder — and comes out in the urine of infected animals,” said Maze. “So even simple things like avoiding urine while doing activities such as, for example, milking cattle would be a good first step.”

Maze recommends abattoir workers and dairy farmers wear gloves and other protective clothing.

“A cow is much bigger and it produces a much larger volume of urine and so that creates a greater opportunity for exposure,” said Maze.

But Maze and colleagues found doctors did not diagnose a single one of the patients in the study with leptospirosis. In fact, one in four active cases was misdiagnosed as malaria — even though the patients’ blood tested negative for parasites.

Symptoms similar

Maze says one reason is because symptoms of the two diseases are similar and there is not an accurate, simple test for leptospirosis that can be run in regional hospitals.

“The second reason is that clinician awareness of these diseases is low,” said Maze. “If you don’t recognize them it becomes a cycle where they’re never diagnosed so you never recognize them.”

Yale’s Albert Ko says the work Maze and his colleagues have done provides a better understanding of how leptospirosis spreads.

Also read: The outbreak of Leptospirosis with monsoon: Symptoms and precautions

“This is an important study specifically because it provides key information on risk factors in a high burden setting, said Ko. “In specifically among this at-risk population of vulnerable pastoralist society.” (VOA)

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Next Story

An Experimental Vaccine to Treat Malaria

Scientists hope to get a better grasp on the system these vaccines employ, known as cellular immunity. Harnessing this system could help tackle hepatitis and HIV infection.

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Vaccines
A doctor assists people looking for treatment for malaria at a health center in San Felix, Venezuela. VOA

After decades of disappointment in efforts to develop a malaria vaccine, researchers are starting to see promise in a new approach.

While most vaccines trigger the body’s defenses to produce antibodies against a disease-causing germ, the new approach recruits an entirely different branch of the immune system.

If it works, it could open up a new route to attack other diseases, including hepatitis and possibly HIV, the virus that causes AIDS.

Nearly 450,000 people die of malaria each year, according to the World Health Organization. The parasites that cause the disease are increasingly becoming drug-resistant.

One successful vaccine has been developed so far, but it prevented only about a third of cases in a clinical study.

Experts have decided that’s better than nothing. The vaccine is being piloted in Ghana, Kenya and Malawi.

Vaccine
Defensive cells killed liver cells that were infected with malaria parasites. (VOA)

New angle

Other scientists are trying a different angle of attack.

There are basically two ways to prevent germs from causing infections. “You either prevent them from getting into cells with antibodies, or you kill them inside the cells with T-cells,” said Stephen Hoffman, chief executive officer of Sanaria, a company working on one vaccine.

Most vaccines target the infection by building up antibodies. “If you need to kill them inside the cells with T-cells, we haven’t been overwhelmingly successful,” Hoffman said.

But Sanaria is one group seeing success by targeting malaria parasites inside infected liver cells, the first stop in the complex life cycle of the disease.

One key difference is how the vaccine is delivered. Hoffman’s group tried a typical route: injecting radiation-weakened parasites into patients’ skin or muscle. That didn’t work.

But it did work when injected directly into veins.

Vaccine
A public health worker takes a blood sample from a woman to be tested for malaria in Bo Rai district, Trat province, Thailand. VOA

The weakened parasites traveled to the liver, where they set off an immune reaction. Defensive cells killed liver cells that were infected with malaria parasites.

And the liver’s defenses were ready when faced with the real thing months later.

Most of that early work has been done in mice and macaques. When Hoffman and colleagues did something similar with a handful of human patients, most were protected against infection.

No waiting

Recruiting immune cells in the liver is especially effective because “we don’t need to wait until the immune system figures out that the parasite is in the liver and starts mounting an immune response, which can take days and sometimes weeks,” said Adrian Hill, director of the Jenner Institute at Oxford University.

“By then, the malaria’s gone. It only spends a week in the liver, and then it’s out in your blood causing disease.”

Vaccine
FILE – A worker of the Ministry of Public Health and Population fumigates in the street against mosquito breeding to prevent diseases such as malaria, dengue and Zika in Port-au-Prince, Haiti, Feb. 15, 2016. VOA

Hill’s group just published a study in the journal Science Translational Medicinein which immune cells in the liver were triggered by using a protein from the parasite, rather than the entire organism.

Scientists hope to get a better grasp on the system these vaccines employ, known as cellular immunity. Harnessing this system could help tackle hepatitis and HIV infection.

Also Read: Alcohol Kills More People Than AIDS, Violence Combines: WHO

Drugs can control HIV infection but can’t eliminate it from the body.

“If somebody could get cellular immunity to work really well for vaccination, that would be transformative for a whole range of diseases,” Hill said. “Not just for infectious diseases that we want to prevent, but ones that we want to treat and we can’t treat today.” (VOA)