Snakebites in Costa Rica Rise Along with El Niño Cycles

Both the hot and cold phases of the El Niño Southern Oscillation (known as El Niño and La Niña, respectively) are accompanied by an increase in snakebites in the Central American country, according to a new study published today (Sept. 11) in the journal Science Advances. Here’s how the climate cycle might be tied to slithering creatures: Snakes are ectothermic, meaning they get their body heat from outside sources. That means their activity is sensitive to climatological factors.

“Snakebites, probably the most neglected of the neglected tropical diseases, [are] another disease showing changes in [the] face of climate change,” study researcher Luis Fernando Chaves, a scientist at the Institute of Tropical Medicine at Nagasaki University in Japan, told Live Science. [See Photos of Snakes from Around the World]

Snakebites are relatively rare in the United States, but pose a huge problem in many regions, particularly southeast Asia and sub-Saharan Africa. A 2008 study published in the journal PLOS ONE found that at least 421,000 people are bitten by venomous snakes worldwide each year, and some 20,000 die — but those are conservative estimates. Given spotty statistics and reporting, the number of bites could be closer to 1.8 million and related deaths might reach 94,000, the authors reported.

Costa Rica is home to 22 species of venomous snake, according to the Costa Rica Star. The one that most often bites humans is the terciopelo (Bothrops asper), which can be deadly without antivenom treatment. [The World’s 6 Deadliest Snakes]
A female Terciopelo snake from the Caribbean basin of Costa Rica.
A female terciopelo from Costa Rica’s Caribbean Basin. In 2013, Discovery producer Steven Rankin was bitten by a terciopelo while scouting a location for the show “Naked and Afraid.”
Credit: Davinia Beneyto
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What made Costa Rica useful for studying snakebites, however, was its widely available and free healthcare system. Not only do doctors keep good records of snakebites in the country, Chaves said, people also have access to healthcare after a bite, meaning even the poorest victims get reported.

Chaves and his colleagues studied a database of snakebites that occurred between 2005 and 2013 — 6,424 in total. They found some predictable patterns: There are fewer snakebites at higher elevations, where the climate is cooler. Every degree Celsius increase in average temperature was linked to a 24 percent increase in the number of snakebites. Poorer areas were harder-hit than wealthier areas, in part because poor people in rural areas are often farmers or farm workers, which puts them in direct contact with snakes, Chaves said. Poverty-stricken citizens are also less likely to have well-built homes that keep snakes out, he added.

Snake weather

The crucial finding, however, was an odd increase in snakebites during both El Niño and La Niña. El Niño brings hot, dry weather to Costa Rica; La Niña brings cool moisture.

It’s simple enough to explain why hot weather might lead to more snakebites: Snakes are more active when it’s warmer, Chaves said. The increase in snakebites linked to the cool weather of La Niña is a little more complicated. The researchers think this increase is linked to El Niño, too, though. Costa Rica has a torrential rainy season, so El Niño’s drier weather (which is just less wet) is actually beneficial for plants compared to the usual deluge, Chaves said. More productive plants translate to more prey animals for snakes, which likely lead to a serpentine population eruption.

This is all well and good for the snakes until the El Niño pattern fades, at which point the snakes lose their abundant food supply. The prospect of starvation probably pushes snakes into areas they wouldn’t normally go — near humans. This delayed reaction to El Niño’s warmth could explain why the number of snakebites goes up again months later, during the cold La Niña. The snakebite count drops again when neither climate pattern is in play, the researchers found.

“This pattern is different from what has been observed for other diseases affected by El Niño,” Chaves wrote in an email to Live Science. “For example, in vector-borne diseases (those diseases transmitted by mosquitoes and other bloodsucking insects), only one phase tends to be important.”

Snakebites qualify as a neglected tropical disease, according to the World Health Organization, partly because victims tend to be poor and living in rural areas, without access to quality healthcare. In Africa, in particular, the need for antivenom outstrips supply, said study researcher José María Gutiérrez, a scientist at the Clodomiro Picado Institute in Costa Rica, which produces antivenoms for Central America.

Adding to the problem, the manufacturer Sanofi Pasteur recently announced it can no longer afford to produce Fav-Afrique, an antivenom effective against 10 sub-Saharan African snake venoms. Supplies — already short — will run out next year.

The Fav-Afrique shortage won’t affect Costa Rica or Latin America, as it’s specific to sub-Saharan snakes, Gutiérrez told Live Science. Clodomiro Picado and other manufacturers do make antivenom for Africa, he said, though they don’t meet the full need.

“The problem of antivenom availability in Africa is much more complex than the decision of a company to stop production,” Gutiérrez said. “It is a multifactorial health problem that demands multifactorial analyses and solutions.”


Say Aaaah Zoo’s Aardvark Gets 2 Teeth Pulled

Getting a tooth pulled is never fun, but it’s especially irksome if you’re an aardvark. Ali, an aardvark at the Cincinnati Zoo, recently learned this lesson firsthand after two infected teeth landed her in the dentist’s chair.

Aardvarks, the only extant species in the order Tubulidentata, are unusual animals — and they have unusual teeth, said Jack Easley, a Kentucky-based veterinarian who specializes in dentistry. Easley was one of several veterinarians who helped extract Ali the aardvark’s two problematic teeth last month at the Cincinnati Zoo.

Unlike most other mammals, aardvarks don’t have enamel in their teeth. (Enamel is the hard, visible part of the tooth that covers up the more sensitive tissues beneath it.) These soft teeth typically serve aardvarks well, because in their native African habitat, the animals only eat easy-to-chew insects like termitesand ants, Easley told Live Science. [Photos: World’s Cutest Baby Wild Animals]But in zoos, aardvarks don’t always eat soft insects, which may not be readily available. Instead, they eat a special, pelleted feed or some other manufactured food, said Easley, who noted that, sometimes, this diet can lead to dental disease. Ali, who is 11 years old, is also middle-age for an aardvark, which may have contributed to the decline in her dental health, he added.

Zoo staff first noticed that there was a problem with the animal’s health back in January, when Ali developed a weird-looking, swollen eye. The problem seemed to be resolved with a dose of antibiotics, but when the medication was finished, the ulcer came back, said Jenny Nollman, an associate veterinarian at the Cincinnati Zoo.

“When it didn’t clear up completely, we investigated it further,” Nollman told Live Science. “That’s when we got into the CT [cat scan] and MRI [magnetic resonance imaging] — the more advanced imaging — to try to really get a better diagnosis.”

In July, zoo staff accompanied Ali to a nearby hospital to try to pinpoint the root of the problem. The CT scan and MRI suggested that what appeared to be an eye problem was actually a tooth problem, Nollman said. That’s when zoo vets reached out to Easley, one of very few veterinarians in the United States who is board-certified in veterinary dentistry.Ali the aardvark’s two infected teeth. Unlike most mammals, aardvarks don’t have a hard layer of enamel covering the crown of their teeth.

Two of Ali’s molar teeth were so infected that the bone and tissue supporting her teeth had formed what’s known as a periodontal pocket, Easley said. This led to the formation of a fistula, or an abnormal passageway between two body parts that are not usually connected. In Ali’s case, the fistula formed between her sinus and the periorbital sac (the tissue surrounding the eyeball), causing her eyeball to look inflamed and leak out pus.

To fix this problem, Easley and another certified veterinary dentist traveled to Cincinnati to pull out Ali’s infected teeth. But there was one small problem: Unlike humans, aardvarks can’t say “ah.”

In addition to having weird teeth, aardvarks have strange mouths. The animals have long tongues and deep oral cavities, with the teeth located all the way in the back (about 12 inches, or 30 centimeters, inside their mouths). These oral openings are very small, measuring only 1.5 inches (4 cm) across, according to Easley.

To reach inside Ali’s mouth, Easley had to make a small incision in the animal’s cheek. After removing the two infected molars, the veterinarians packed the hole left by the extracted teeth with an antibiotic-coated gauze material and left Ali to heal over the next three to six weeks.

Yesterday (Sept. 1), Nollman performed a checkup, and the resilient little aardvark seemed to be doing quite well, she said, though it will take Ali a few more weeks to fully heal.

“[Ali] has not missed a beat through this whole thing,” Nollman said. “Her appetite has never decreased, and she has been very active.”

Birds of a Feather Photos of Hummingbirds Hawks & Jays

In the Chiricahua Mountains of Arizona, black-chinned hummingbirds have a clever strategy to keep their nests safe: They recruit unknowing hawks for home security. Hummingbird nests cluster near hawk nests, and those hawks keep away the predatory jays that snatch hummingbird eggs, researchers reported Sept. 4 in the journal Science Advances. A female black-chinned hummingbird (Archilochus alexandri) perches on a twig. The daily survival rate of a hummingbird nest built nearby a hawk’s nest is 31 percent, compared with only 6 percent for hummingbird nests not near hawk roosts. (Credit: Harold F. Greeney, Yanayacu Biological Station

Pet Scam The Animal Control Officer Who Wants Cash

On the heels of pet-flipping comes the latest ruse facing dog owners: Scammers posing as animal control officers.

It’s occurred sporadically but not extensively in the past.  Now it seems on the rebound – at least in retiree-rich South Florida. TV station WPTV reports a case in which a couple living in an over-55 community lost $550 to an imposter claiming there had been complaints about the couple’s dog.  He threatened to impound the pooch unless they immediately paid. They obliged.

“He had a badge, had an ID, gave us a business card and represented himself completely as being part of an independent company for animal care and control,” said the community’s HOA president.

If you’re approached the same way, don’t be fooled. Better to make a quick call to the local Animal Control department – or its reported vendors – to check such claims, no matter what paper “proof” of authority is represented.

“If anybody comes to your house and says give me money. I’m from the county. I’m going to take your dog. That’s not us,” said an official with Palm Beach County Animal Care and Control Operations.