Bacteria crucial for tick reproduction offers new disease control strategies - study

Ticks – small, spider-like creatures with six or eight legs and as small as a pencil point that feed on the blood of dogs, birds, and sometimes cats – are annoying and can be dangerous, so veterinarians recommend applying anti-tick medications monthly on the backs of pets’ necks or anti-tick collars.

Australia is home to bush ticks found along parts of the east and west coasts. One type, which attaches itself to a dog’s body, can cause babesiosis, paralyzing and even killing the unfortunate animal within hours if not removed immediately; the pet is given medication.

Ticks can also bite humans, although most of those bites are harmless and painless. While most tick bites on humans don’t necessitate medical attention, some, such as the wood tick, deer tick, and others, can harbor harmful germs that lead to diseases like Rocky Mountain spotted fever, Lyme disease (found in some caves in Israel), and anaplasmosis, among others. These diseases can cause severe health issues, including neurological problems, joint pain, and even death if not properly treated. The ticks fall off on their own after sucking blood for three to six days, after which a little red bump – the body’s response to the bug’s saliva – appears.

They’re attracted to moist, warm areas of the body, including the upper back, scalp, calf/shin, upper arm, behind the knee, armpit, neck, and lower back. Bug repellents with at least 20% DEET on all exposed skin can be used to keep them away.

If you find a tick crawling on you, brush it off. Engorged ticks contain potentially infected blood that can splatter when crushed, so never crush it with your fingers.

A NEW STUDY at the Hebrew University of Jerusalem (HU) provides insights that could lead to innovative ways to combat ticks. The researchers, led by Prof. Yuval Gottlieb-Dror from the Koret School of Veterinary Medicine in Rehovot, discovered that certain bacteria living inside ticks are essential for their survival and reproduction. 

Key bacteria vital for tick reproduction

The research paper, titled “Endosymbiont-derived metabolites are essential for tick host reproductive fitness,” has just been published in mSphere of the American Society of Microbiology.

These pathogens produce vital nutrients that ticks can’t get from their blood-only diet. This finding is significant because it uncovers a potential vulnerability in ticks that could be exploited. By targeting these beneficial bacteria, one could more effectively control tick populations, potentially reducing tick-borne diseases in humans and animals, the researchers noted. The research, the team said, offers a novel approach to fighting ticks by disrupting their internal support system, rather than solely attempting to kill the ticks directly.

The important information they discovered was about the relationship between the brown dog tick, Rhipicephalus sanguineus, and its Coxiella-like symbiotic bacteria. The research shows that these bacteria help the ticks by providing essential B vitamins and possibly other nutrients like L-proline, which are crucial for the bug’s reproduction and health.

Understanding the biological mechanisms that support tick survival and reproduction is crucial for developing new methods to prevent tick bites and reduce the incidence of tick-borne diseases, ultimately protecting public health. According to the US Centers for Disease Control and Prevention (CDC), about 50,000 people visit emergency departments annually due to tick bites in the US alone. This number likely underestimates the total number of tick bites, as many bites do not result in emergency visits and are unreported.

Gottlieb and her colleagues measured amino acid levels and examined the effects of B vitamins and L-proline supplementation on female ticks with suppressed Coxiella-like endosymbionts.

The findings revealed that L-proline levels were higher in the symbiont-hosting (structures that house populations of beneficial microbes) unfed ticks and in engorged blood-fed ticks. Moreover, the supplementation of B vitamins significantly increased the hatching rate of ticks with low levels of Coxiella-like endosymbionts, an effect that was further enhanced with the addition of L-proline. These results suggest that Coxiella-like endosymbionts produce L-proline and are essential for the tick’s reproductive processes, especially when there is a high metabolic demand such as egg production and embryonic development.

“This study underscores the importance of nutritional symbionts in the health and reproduction of ticks,” said Gottlieb. “Our findings can open new possibilities for developing strategies to control tick populations and diseases,” she concluded.