Since the global pandemicSince 2020, the world has been more conscious that our species’ health is interconnected with the health of other animals. Today, the conversation is mostly focused on birds and mammals, with amphibians rarely considered – but that may be a dangerous oversight.
A study published in the Journal of Frog Research and malaria illustrates how intimately human health may be impacted by these lovable – if somewhat slimy – creatures.
In the 1980s, ecologists from Panama and Costa Rica began to notice a steady decline in amphibian population numbers.
In this region, salamanders as well as frogs were suffering from a fungal disease.Batrachochytrium dendrobatidis), and they were doing so at such a rapid rate that researchers at the time feared a wave of local extinctions.
Scientists now believe this pathogen, Bd, is responsible for the majority of cases. causedThe “greatest recorded loss of biodiversity due to a disease” was responsible for the declines in at most 501 amphibian species from Asia to South America.
Although this is an enormous claim, amphibians are now included in the list of endangered species. These are the most endangered groups of animals on EarthThis is at least partially to blame for the spread of this fungus worldwide and other fungi like it.
Frogs and salamanders directly influence mosquito population sizes because mosquitoes are a key source of food, which means the numbers of amphibians could ultimately influence the vectors – living organisms that can transmit infectious pathogens – that spread deadly human diseases.
Researchers have used Central America as a case study to show how frogs can ultimately be beneficial for human health.
These were the findings First presented in 2020, have now been peer-reviewed, and they show that Bd-driven amphibian losses led to a substantial increase in the incidence of malaria – a disease transmitted by infected mosquitoes – first in Costa Rica in the 1980s and 1990s, and then again in Panama in the early 2000s, as the fungus spread east.
The authors believe this to be the first direct evidence of amphibian loss affecting human health in a natural setting.
To estimate the causal effect of Bd-driven malaria decline at the county level in Costa Rica or Panama, the study used a multiple regression model.
Researchers discovered a clear pattern in the amphibian incidence map and the malaria decline map from 1976 to 2016. This pattern could be predicted with high accuracy by their model.
Eight years after severe amphibian losses from Bod, there was an increase in malaria cases that equaled about one case per 1,000 people. The recent amphibian deaths would not have led to this additional case.
The incidence rate of malaria is usually between 1.1 and 1.5 cases per 1,000 people during an outbreak. This could indicate that there was a possible 70-90 percent increase of the number people who were becoming sick due to the loss of Central American amphibians.
The paper’s authors wrote that the pattern showed a west-to east wave from the Costa Rican northwestern border in 1980 to the Panama Canal region in 2010.
However, researchers have found that the expected effect has dropped suddenly after eight years.
According to the authors, it is possible that an increase in cases of malaria leads to a greater use and subsequent decrease in cases.
Future research on other mosquito-borne disease, such as dengue, may help to support the link between amphibian loss, and an increasing threat from mosquitoborne diseases.
Researchers could only obtain some data from Panama on dengue cases, not at county-level. However, these findings suggest that dengue has increased following the decline of amphibians.
The increase in dengue cases between 2002 and 2007 was 36% compared to the eight previous years.
The authors write that “This previously unknown impact of biodiversity loss illustrates often hidden human welfare costs associated with conservation failures.”
“If scientists or decision-makers fail in their ability to consider the consequences of past events, they risk not being able to motivate protection against future calamities like international spread of a closely related pathogen.” Batrachochytrium salamandrivorans“Through incompletely regulated live-species trade,” they say.
This is what you will see as you read it. B. salamandrivoransGlobal trade is a sailor on the move, and it threatens both the future of amphibians as well as the health of our species.
The current study shows that frog health and human health often go hand in hand. We all are tied together, whether we like or not.
The study was published by Environmental Research Letters.
