Who’s Got a Dictionary? (AKA: Translators wanted)

My friend and I were having a conversation the other day about the disconnect that can happen between science and people in the field. It can be hard to decipher scientific publications and find out if the information is directly relevant and if we can use it to improve how we do things. This means taking the time to read through and not just look at the results, but how the experiments were done.

So let’s take a look.

I had this article hit my alerts the other day.

Translating the title into something more general:

Population fluctuations – okay, this one is pretty easy. The number of individuals in a given polulation will change.

and synanthropy – google says: A synanthrope is an organism that evolved to live near humans and benefit from human settlements and their environmental modifications. (yes, I had to look that up.) We are talking about what our industry usually refers to as “commensal”.

explain transmission risk – again, pretty simple: how easy or difficult it is to have something carried by rodents to impact people.

in rodent-borne zoonoses – google again: A zoonosis is any disease or infection that is naturally transmissible from vertebrate animals to humans.

Industry translation – changes in population and type of animal (rodent) determine how likely it is for a person to acquire a rodent-borne disease.

Great! So, how did they figure this out?

We collated or calculated s-index, which measures the degree of population fluctuation, across all rodent species for which data were available. This global dataset also includes life history traits, reservoir status for zoonotic pathogens, habitat associations, and spatial distributions of 436 rodent species. We use these data to test hypotheses about factors characterizing the probability that rodents would pose a strong risk for zoonotic spillover. Specifically, we hypothesised that synanthropic rodents would be overrepresented in the pool of rodent species identified as zoonotic reservoirs. We also hypothesised that zoonotic reservoir species, compared to non-reservoirs, would exhibit large population fluctuations and be habitat generalists. While we predicted that large population fluctuations are an important characteristic of rodent reservoirs, we also hypothesised that exploitation by humans (e.g., by hunting for meat and fur) poses increased transmission risk. We show that the magnitude of population fluctuations combined with species’ synanthropy and degree of human exploitation together distinguish the vast majority of zoonotic rodents at a global scale.

You got all that right?

Translation – we read a whole lot of scientific articles on this and made that into one huge data set. We guessed that commensal species would be more studied (more articles written) for diseases. Also, we figured that the species that carried the diseases would be found in lots of different habitats. And, people who spend time in these rodent habitats are more likely to catch a rodent borne disease than those not around rodents.

That makes sense. Papers like this are great because, while they didn’t do any experiments in the lab or field, they went through all the literature they could find and combined it. It means they can essentially have one giant data set instead of lots of little ones scattered around. When experiments are run, I look for things like where (lab or field), how many (did they test a lot or a few), and more to see how it relates to what we do on a daily basis.

I’m not going to go through all the results, and I won’t make you try out your translation skills, but here are some key items:

• They looked at a total of 95 known zoonotic pathogens (34 viruses, 26 bacteria, 17 helminths, 12 protozoa and six fungi).

• Species that typically carried rodent borne diseases were highly commensal.

• People who hunted/worked around commensal rodents were at five times the risk of those working around non-commensal species.

• Species were more likely to be a reservoir with increasing adult weight. (This is kinda cool info!)

• Commensal species experienced higher population fluctuations.

• Transmission risk increases with rodent abundance. (Makes sense.)

• Reservoir species thrive in human-created (artificial) habitats, and more of them exist in artificial habitats. (No surprise there.)

• Therefore, changes in communities through changing natural habitats (into housing, farming, or other development) increase transmission risk.

• Natural habitats, due to their high species diversity, pose less risk of zoonotic transmission compared to artificial habitats. (There is more disease transmission in “people” areas.)

Bottom line:

Rodents that can carry disease (our Norway rat, roof rat, and house mouse primarily) are more likely to be found in habitats where people live. The chance of getting one of these diseases increases if you are working with or in areas where these rodents are prevalent. Rodent control is key to protecting people’s health and well-being. Especially those who do rodent control need to take precautions against those diseases.

If you think your rodent control program could use a look and be updated, contact us. We will go through the science so you don’t have to, and you get more effective solutions.

Lagniappe - really, go look at the paper, it's got great graphics and info.