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A cross-divisional department spanning

One Health Laboratory at Johns Hopkins University

COVID-19 Human-Animal Interactions Survey (CHAIS)

General Description

The COVID-19 Human-Animal Interactions Survey (CHAIS) was developed to provide a standardized survey describing human-animal interaction during the COVID-19 pandemic. The CHAIS instrument evaluates behavioral, spatiotemporal, and biological risk factors associated with bi-directional zoonotic transmission of SARS-CoV-2 (CoV-2) within households and other shared environments. CHAIS is also highly adaptable for use in studies seeking to investigate other zoonotic pathogens that share similar disease transmission to CoV-2, such as influenza viruses. This standardized instrument will enable pooling of data across studies for meta-analyses to improve predictive models of bi-directional transmission of SARS-CoV-2 among humans and animals and other similarly transmitted disease.


SARS-CoV-2 (CoV-2), which surfaced in late 2019 in Wuhan City, China, most likely originated in bats and rapidly spread among humans globally, harming and disrupting livelihoods worldwide. Early into the pandemic, reports of CoV-2 diagnoses in pets and other animals emerged, including dogs, cats, farmed mink and some large felids (tigers and lions) from various countries. While most CoV-2 positive animals were confirmed to have been in close contact with CoV-2 positive humans, there remains a scarcity of evidence to-date describing risk factors associated with CoV-2 transmission among humans and domestic and wild animals. While there are many studies that have evaluated human animal interactions for CoV-2 and other zoonotic and reverse zoonotic disease, no standard instrument exists.  We developed CHAIS to help capture these risk factors and to standardize how human animal interactions information is being acquired, not only for use when evaluating CoV-2 but other similar diseases.

CHAIS: The COVID-19 Human Animal Interactions Survey


What is CHAIS?

CHAIS is a standard survey instrument that captures risk factors of COVID-19 transmission among humans and animals by gathering information on human pet interaction predominately inside the home. 
The COVID-19 Human-Animal Interactions Survey (CHAIS) evaluates four broad domains of transmission risk: 1) intensity and risk of infection among human hosts, 2) spatial characteristics of shared environments, 3) behaviors and human-animal interactions, and 4) animal susceptibility to infection.

What is the goal of CHAIS?

The purpose of CHAIS is to provide a standardized instrument that will capture human animal interactions and disease transmission risk of not only CoV-2, but other similarly transmitted diseases. By providing a standard instrument CHAIS will enable pooling of data across studies for meta-analyses to improve predictive models of human and animal transmission of SARS-CoV-2, and other disease, and help inform public health prevention and mitigation measures.

ACCESS CHAIS Instrument here: Link to RedCap with CHAIS instrument-coming soon-

How was CHAIS developed?

CHAIS was developed through a cross-CEIRS Center collaboration between laboratories at Tuffs and Johns Hopkins to provide a standardized survey describing human-animal interaction during the pandemic and to evaluate behavioral, spatiotemporal, and biological risk factors associated with reverse zoonotic transmission of CoV-2 within households and other shared environments.

Who should use CHAIS?

Any research team collecting information about household pets in the context of human-animal interactions. 

What is the structure of CHAIS?

The CHAIS instrument is offered in two formats, an extended version, E-CHAIS, and an abridged version, A-CHAIS, which is comprised of only questions that directly address universal domains associated with reverse zoonotic transmission. Both versions encompass eight modularizable sections that capture various aspects of human-animal interactions during the COVID-19 pandemic, pet susceptibility to infection, human and animal risk factors and behaviors, and spatiotemporal factors. The questionnaire comprises primarily closed-ended questions with multiple choice responses, as well as follow-up questions based on answers provided. 

Modularizable sections:

1. Household Demographic 5. Human-Animal Interaction
2. Pet Demographic and Behaviors 6. Human Illness History/COVID-19 Section
3. Occupation Section 7. Animal Worker Section
4. Travel and Activities Section 8. Pet Health History

How to use CHAIS in your research study

Each of the eight modules can be considered individual sub-instruments. Individual studies can deploy and use the survey in one of several ways. 

  1. Incorporate either extended or abridged versions of the survey en bloc within their study;
  2. Select individual modules from either the extended and/or abridged versions of CHAIS and use them independently or in conjunction with another instruments;
  3. Use individual modules in their entirety with the selection of individual questions from other modules; 
  4. Select individual questions and cite the CHAIS instrument as the source which will allow traceability of the instrument’s usage. 

How to cite CHAIS?

While the CHAIS instrument is adaptable, the offering of multiple versions and independent modularizable sections allows for standardization of pet contact instruments when properly citied. Researchers who use either E-CHAIS or A-CHAIS en bloc will simply name one or both instruments with citation, whereas researchers who use a modular approach, such as those already conducting research with need for only certain types of questions covered in specific modules, are encouraged to name the individual modules with citation.

Table 2. Citation guidance for individual sections for both extended and abridged versions of the CHAIS instrument. The numbers associated with each section represent the question count for that version of CHAIS. 

Sections Extended CHAIS
Abridged CHAIS
Household Demographic DEM-12 DEM-11
Pet Demographic and Behaviors PetDEM-12 PetDEM-6
Occupation Section Occ-6 Occ-2
Travel and Activities Section Travel-10 Travel-3
Human-Animal Interaction HAI-16 HAI-14
Human Illness History/COVID-19 Section HMNill-19 HMNill-12
Animal Worker Section AW-7 AW-4
Pet Health History PetHlth-27 PetHlth-12
Total number of questions 109 64

Evidence to-date of CoV-2 transmission and susceptibility among common household pets and other animals



Common interfaces for human-animal interactions associated with reverse zoonotic transmission of respiratory pathogens


The CHAIS instrument focuses on interfaces where animals and humans share close contact, including households, farms, and veterinary settings. Reverse zoonotic transmission events of CoV-2 and other zoonotic pathogens have been postulated to be due to direct interactions between human hosts and animals, specifically kissing, cuddling, playing, feeding, and sleeping habits. Given widespread prevalence of COVID-19 in human populations, the CHAIS instrument seeks to uncover behavioral risk factors and important interfaces for reverse zoonotic transmission events from humans to animals. Not pictured here, the CHAIS instrument also addresses biological and spatiotemporal risk factors underlying these events.

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