Zoonotic and vector-borne emerging tropical diseases pose a constant threat

A recent article published in the journal Frontiers in Tropical Diseases assessed the threat of emerging zoonotic and vector-borne tropical diseases.

This review, which was published as a Specialty Grand Challenge, addresses the challenges, drivers of the emergences, as well as root causes of these tropical diseases in an effort to reduce their impact.

An overview of concerning infectious diseases

Several different infectious diseases impact the health of humans around the world. Some of these diseases include:

• Chikungunya
• Zika
• Yellow Fever
• Dengue
• Oropouche
• Madre de Dios virus
• Iquitos virus
• Mayaro Fever
• Ebola, Nipah virus
• Arenaviruses (i.e., Lassa)
• Machupo
• Chapare
• Junin
• Zoonotic Malaria
• Severe Fever with Thrombocytopenia Syndrome
• Plague
• Crimean-Congo Hemorrhagic Fever
• Acute Orally Transmitted Chagas Disease
• Visceral and Diffuse Cutaneous Leishmaniasis
• Toxoplasmosis
• Tick-borne Diseases
• Rift Valley Fever
• Tuberculosis
• Leprosy
• Avian Influenza
• Orthohantavirus
• Toxocariasis.

In addition to the aforementioned diseases, zoonotic epidemics and pandemic coronaviruses, such as the Severe Acute Respiratory Syndrome (SARS), the Middle East Respiratory Syndrome (MERS), and the SARS-coronavirus 2 (SARS-CoV-2), which is the virus responsible for the coronavirus disease 2019 (COVID-19) and current pandemic, continue to pose a deadly threat to public health.

Aside from the concern that these diseases cause to the general public health, the prevalence of coinfections, such as those between tropical pathogens and COVID-19, is becoming increasingly evident.

There has also been a significant increase in mortality and morbidity rates related to the emergence of infectious diseases – vector-borne, zoonotic, and environmentally transmitted, as well as the effects of environmental alterations, such as climate change.

How can the spread of infectious diseases be mitigated?

Despite the known impacts of these viruses on global health, there remains a lack of necessary funding opportunities and, as a result, an urgent need for extensive research in emerging tropical diseases. As the world is no longer a place of distant countries and shielded territories, the authors reasoned that the health status of the underprivileged does not only alter their lives and development but extends to those residing in wealthier areas. As a result, a new funding paradigm is needed, one that combines both advanced research with technological solutions.

One example that was referenced was the Ebola crisis in 2014. During this crisis, it became evident how high-consequence emerging diseases could spill over to Europe and North America. Likewise, the ongoing 2020-2021 pandemic of the pervasive COVID-19 has spread to almost every country across the world, even reaching as far as Antarctica.

Some of the available tools to counteract emerging infectious diseases include active surveillance (also by artificial intelligence) and rapid identification of novel pathogens by genome sequencing and phylogenetic tracing studies.

More specifically, these studies use computing methods that predict interspecies barriers that may spill over between human and animal populations. Taken together, the coupling of biotechnological approaches and social sciences appears to be a critical element for studying emerging infectious diseases.

The complexity and heterogeneity of many tropical infectious diseases remain a challenge in fully understanding the diseases themselves.

Designing proposed interventions, including multilevel eco-epidemiological studies ranging from molecular and omics to satellite epidemiology of pathogens, vectors, hosts, abiotic variables, as well as examining other socio-environmental factors, are some of the steps that are needed to better approach these diseases.

Vaccine development is also a significant arm in mitigating the transmission and severity of these diseases.

Importantly, the authors clarified that “Tropical Medicine is no more a clinical specialty of ‘exotic diseases,’ as it was conceived at its beginnings, and is no more about diseases for those entering the jungle.”

Increases in epidemics in cities are a reminder of the drastic changes in diseases over the past century. Notably, tropical diseases also include non-infectious diseases, such as animal bites and stings like snake bites, scorpion stings, and spider bites.

Aside from the factors mentioned above, integrating the expertise of the various specialists is of utmost importance in mitigating tropical diseases. These include public health experts, veterinarians, entomologists, and parasitologists, as their knowledge is required to face these new challenges and transform the outcomes of tropical diseases.

The future ahead

In conclusion, the authors described how we are “living on the edge” – the edge of neglect and a surge of many emerging infectious diseases with no hope for resolution in the foreseeable future.

Factors such as poverty, inequality, climate change, deforestation, migration, urbanization, and wildlife trade, to name a few, have contributed to the emergence of novel tropical diseases and the resurgence of other endemic diseases.

“Research in Zoonotic and Vector-Borne Emerging Tropical Diseases remains the most critical aspect and the foundation to determine the drivers of emerging and re-emerging infectious diseases.”

With the high possibility of another epidemic/pandemic in the near future, the authors of this study, all of whom are editors of Frontiers in Tropical Diseases, introduce a new section of the journal known as Emerging Tropical Diseases. The aim of Emerging Tropical Diseases is to help contribute to scientific advancements and fill in the numerous knowledge gaps that exist for many of these tropical diseases through a multi- and transdisciplinary approach.

The authors invite the general public to address this constant threat and begin submitting their work to the new section of Frontiers in Tropical Diseases.

Written by

Dr. Ramya Dwivedi

Ramya has a Ph.D. in Biotechnology from the National Chemical Laboratories (CSIR-NCL), in Pune. Her work consisted of functionalizing nanoparticles with different molecules of biological interest, studying the reaction system and establishing useful applications.