A potential pandemic threat: Evolution of Dog-Related Viruses to Human Viruses
Creators: name: Hussain, Zahid
Publisher: name: Zenodo
Year: 2024
Subjects: potential
pandemic
threat:
Evolution
Dog-Related Viruses
Human Viruses

description: A potential pandemic threat: Evolution of Dog-Related Viruses to Human Viruses

The cross-species transmission of viruses has been a significant factor in the emergence of human infectious diseases. Viruses that originally infected dogs, or canines, have occasionally adapted to infect humans. This evolutionary process highlights the interplay of viral genetics, host susceptibility, and environmental factors. Understanding these dynamics is crucial for predicting and preventing future zoonotic events.

Introduction

Canines, including domestic dogs and their wild relatives, have been close companions to humans for millennia. However, their proximity also creates opportunities for viral spillover. Zoonotic transmission, where pathogens jump from animals to humans, is often driven by close interactions and shared environments. While most viruses are species-specific, certain conditions allow for interspecies transmission.

Objectives

This report aims to:



Explore the mechanisms enabling viruses to cross from canines to humans.

Examine examples of canine-origin viruses infecting humans.

Analyze the evolutionary and genetic changes facilitating such transmissions.

Discuss implications for public health and preventive strategies.


Mechanisms of Viral Spillover

Host Specificity and Receptor Binding

Host specificity in viruses is primarily determined by the ability of viral proteins to bind host cell receptors. For instance, the canine distemper virus (CDV) uses the SLAM (Signaling Lymphocyte Activation Molecule) receptor, which has homologs in humans. Mutations in viral proteins can broaden host range, enabling infection of humans.

 

 

Genetic Recombination and Mutations

Viruses such as coronaviruses and parvoviruses frequently undergo genetic recombination and mutations. These genetic changes can enhance their ability to replicate in a new host. In canine coronaviruses (CCoVs), mutations in the spike (S) protein have been linked to cross-species transmission.

Human-Canine Interactions

Human activities such as pet ownership, veterinary practices, and wildlife exploitation increase the likelihood of viral exchange. Prolonged exposure, such as during care for infected animals, facilitates zoonotic events.

Examples of Canine-Origin Viruses Infecting Humans

Canine Parvovirus (CPV)

Origin and Evolution

CPV emerged in the 1970s as a variant of feline panleukopenia virus (FPV). Although CPV primarily infects canines, it has been found in humans with compromised immune systems, raising concerns about its zoonotic potential (Decaro & Buonavoglia, 2012).

Genetic Adaptation

Studies show that CPV’s VP2 protein underwent mutations to enhance binding to canine transferrin receptors, a change that might also permit occasional human infections (Shackelton et al., 2005).

Canine Distemper Virus (CDV)

Zoonotic Potential

CDV, a Morbillivirus closely related to measles, primarily infects canines but has been detected in human serum samples during outbreaks. The similarity between CDV and human measles virus suggests a common ancestor, highlighting potential evolutionary pathways (Martella et al., 2008).

 

Molecular Evidence

Genomic studies reveal that CDV’s hemagglutinin (H) protein could theoretically bind human SLAM receptors, making cross-species infections plausible under certain conditions (Panzera et al., 2015).

Canine Coronaviruses (CCoVs)

Emergence in Humans

Canine coronavirus-HuPn-2018, identified in a pneumonia patient, represents a notable example of canine-origin viruses infecting humans. This recombinant virus contains elements from canine, feline, and porcine coronaviruses, underscoring the complexity of viral evolution (Vlasova et al., 2021).

Genetic Adaptation

Mutations in the spike protein’s receptor-binding domain (RBD) facilitated human cell entry, a critical step for cross-species infection (Vlasova et al., 2021).

Evolutionary Dynamics

Genetic Drivers of Zoonosis

Mutations in Key Viral Proteins

Point mutations in proteins such as hemagglutinin or spike proteins are often necessary for host-switching events. For example, amino acid substitutions in CCoV’s spike protein have been implicated in human infections (Vijaykrishna et al., 2007).

Reassortment and Recombination

Reassortment occurs when segmented viruses exchange genetic material during co-infection. In the case of CCoVs, this mechanism has been observed, contributing to their adaptability and zoonotic potential (Zhang et al., 2018).

Host Immune Response

Human immune responses play a dual role in cross-species transmission. While robust immune barriers often prevent zoonosis, immunosuppressed individuals or those with pre-existing conditions are more susceptible to novel pathogens.

Environmental and Ecological Factors

Urbanization and Wildlife Encroachment

Urbanization has increased interactions between humans and domesticated or wild canines. Such environments act as hotspots for zoonotic spillover (Daszak et al., 2000).

Climate Change

Climate change influences the distribution of canine populations and their viruses. For instance, warming climates expand the range of canine reservoirs, increasing exposure risk to humans (Hoffmann et al., 2019).

Public Health Implications

Surveillance and Monitoring

Early Detection Systems

Enhanced genomic surveillance can identify genetic changes in canine viruses with zoonotic potential. Sequencing efforts should focus on areas with high human-canine interaction.

Diagnostic Tools

Improved diagnostic assays can aid in early detection of canine-origin viruses in humans. Multiplex PCR assays are particularly useful for identifying recombination events.

Vaccination Strategies

Cross-Species Vaccines

Developing vaccines targeting conserved viral epitopes could protect both canines and humans, mitigating zoonotic risks.

 

 

Herd Immunity in Canines

Vaccinating domestic dogs against key viruses like CDV can indirectly protect human populations.

Public Awareness Campaigns

Responsible Pet Ownership

Educating pet owners about the risks of zoonotic transmission can reduce exposure. Hygiene measures such as handwashing after handling animals are critical.

Wildlife Management

Programs aimed at reducing contact between humans and wild canines can minimize spillover events.

Conclusion

The evolution of dog-related viruses to human viruses represents a complex interplay of genetic, ecological, and social factors. While zoonotic events are relatively rare, their potential consequences for public health necessitate vigilance. Advances in genomics, surveillance, and vaccination hold promise for mitigating these risks. By addressing the drivers of zoonosis, we can better prepare for and prevent future outbreaks.

 

 

 

 

 

 

 

 

 

 

References