One Health Publications

Outbreaks of clinical toxoplasmosis in humans: five decades of personal experience, perspectives and lessons learned

May 24, 2021

Abstract Background:

The protozoan parasite Toxoplasma gondii has a worldwide distribution and a very wide host range, infecting most warm-blooded hosts. Approximately 30% of humanity is infected with T. gondii, but clinical toxoplasmosis is relatively infrequent. Toxoplasmosis has a wide range of clinical symptoms involving almost all organ systems. In most persons that acquire infection postnatally, symptoms (when present) are mild and mimic other diseases such as flu, Lyme disease, Q fever, hematological alterations, or mumps. It is likely that clinical disease is more common than reported. The ingestion of infected meat or food and water contaminated with oocysts are the two main modes of postnatal transmission of Toxoplasma gondii. The infective dose and the incubation period of T. gondii infection are unknown because there are no human volunteer experiments.

Methods: Here, I have critically reviewed outbreaks of clinical toxoplasmosis in humans for the past 55 years, 1966– 2020. Information from oocyst-acquired versus meat-acquired infections was assessed separately.

Results: Most outbreaks were from Brazil. There were no apparent differences in types or severity of symptoms in meat- versus oocyst-acquired infections. Fever, cervical lymphadenopathy, myalgia, and fatigue were the most important symptoms, and these symptoms were not age-dependent. The incubation period was 7–30 days. A genetic predisposition to cause eye disease is suspected in the parasites responsible for three outbreaks (in Brazil, Canada, and India). Only a few T. gondii tissue cysts might suffice to cause infection, as indicated by outbreaks affecting some (but not all) individuals sharing a meal of infected meat.

Conclusions: Whether the high frequency of outbreaks of toxoplasmosis in humans in Brazil is related to environmental contamination, poor hygiene, socioeconomic conditions, or to genotypes of T. gondii needs investigation.

Keywords: Toxoplasma gondii, Ocular, Outbreaks, Meat, Oocysts, Humans, Worldwide


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A proposal to leverage high-quality veterinary diagnostic laboratory large data streams for animal health, public health, and One Health

May 22, 2021

*Craig N Carter 1Jacqueline L Smith 1


Test data generated by ~60 accredited member laboratories of the American Association of Veterinary Laboratory Diagnosticians (AAVLD) is of exceptional quality. These data are captured by 1 of 13 laboratory information management systems (LIMSs) developed specifically for veterinary diagnostic laboratories (VDLs). Beginning ~2000, the National Animal Health Laboratory Network (NAHLN) developed an electronic messaging system for LIMS to automatically send standardized data streams for 14 select agents to a national repository. This messaging enables the U.S. Department of Agriculture to track and respond to high-consequence animal disease outbreaks such as highly pathogenic avian influenza. Because of the lack of standardized data collection in the LIMSs used at VDLs, there is, to date, no means of summarizing VDL large data streams for multi-state and national animal health studies or for providing near-real-time tracking for hundreds of other important animal diseases in the United States that are detected routinely by VDLs. Further, VDLs are the only state and federal resources that can provide early detection and identification of endemic and emerging zoonotic diseases. Zoonotic diseases are estimated to be responsible for 2.5 billion cases of human illness and 2.7 million deaths worldwide every year. The economic and health impact of the SARS-CoV-2 pandemic is self-evident. We review here the history and progress of data management in VDLs and discuss ways of seizing unexplored opportunities to advance data leveraging to better serve animal health, public health, and One Health.




*Dr. Carter is a member of the One Health Initiative team.

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Questions remain after WHO team visits Wuhan looking for answers to SARS-CoV-2

May 21, 2021

Issue: May 2021

By Arnon Shimshony, DVM

“… The report underlines the need for further trace-back at the wildlife farms that previously supplied the Huanan market and other Wuhan markets linked to positive cases, to include interviews and serological testing of farmers and their workers, vendors, delivery staff, cold-chain suppliers and other relevant people and their close contacts. The team concluded: “Surveys should be designed using a One Health approach in larger areas and more countries, including genomic surveys and structured serosurveys of high-risk potential reservoir hosts and their human contacts.

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Two more coronaviruses can infect people, studies suggest

May 20, 2021

“… Gregory Gray [MD, MPH] at Duke University, senior author on the Malaysian chimeric coronavirus study, also advocates for surveillance among pneumonia patients in areas known to be hot spots for novel viruses or places where large populations of animals and humans mix, such as live animal markets and large farms. “These spillovers take years,” Gray says. “It’s not like in the movies. They go through different steps to infect humans.” So far indications are that the chimeric virus has not evolved to transmit efficiently between people.”

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Another new coronavirus has jumped to people

May 20, 2021

By Lianna Matt McLernon | News Writer | CIDRAP News – May 20, 2021

“… Because of these virus spillovers, Gray, Toh, and Vlasova continue to advocate for a focus on human-animal nexus surveillance. As Gray and co-author Anfal Abdelgadir, BDS, MSc, write in a 2021 Open Forum Infectious Diseases commentary, more human-animal interaction inevitably creates opportunities for novel strains, but it can take years of evolution and ineffective spillovers for these pathogens to become infectious and transmissible among humans.

“The most strategic approach would be directing periodic, novel respiratory virus surveillance at the human-animal interface, studying both animal workers and their animals,” they write, advocating for a One Health approach, which looks at the holistic and interconnected relationships between all organisms’ health and is being highlighted today by the World Health Organization. …”

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United Nations (U.N.) bodies set up ‘One Health’ panel to advise on animal disease risks

May 20, 2021

May 20, 2021

SHANGHAI (Reuters) – The World Health Organization and three other international bodies have formed a team of experts to help develop a global plan to prevent the spread of diseases from animals to humans, the WHO said on Thursday.

The One Health High-Level Expert Panel was an initiative launched by France and Germany late last year, and held its inaugural meeting this week.

It will advise the WHO, the Food and Agriculture Organization, the World Organization for Animal Health and the United Nations Environment Programme on developing “risk assessment and surveillance frameworks” and establish “good practices to prevent and prepare for zoonotic outbreaks.” 


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One Health Social Sciences webinar “Interprofessional Education & One Health: How ready are MD and DVM students?”

May 19, 2021

By Professor Rohini R. Roopnarine, DVM, M.Phil, EdD (Higher Ed.), MRCVS
Veterinary Public Health & Epidemiology

Course Director: GVH Track (UK): Vet. Pub Health, School of Veterinary Medicine

Adjunct Professor, Dept. Public Health & Prev Med.

School of Medicine, St. George’s University, True Blue, St. George’s Grenada, WI

The presentation slides (made available by Dr. Roopnarine and uploaded to the 1HOPE folder) can be viewed at:

For more detail, see: Roopnarine R. Factors That Influence the Development of Interprofessional Education and One Health for Medical, Veterinary and Dual Degree Public Health Students at an Offshore Medical School. Doctor of Education thesis, University of Liverpool. 2020

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At times of Covid: Egypt launches programmes to combat antimicrobial resistance

May 18, 2021

The programmes are meant to raise healthcare providers’ awareness about the importance of curbing the overuse of antibiotics

“… The initiative comes in conjunction with the “One Health” approach announced by the WHO to design and implement programmes, policies, legislation, and research to achieve the best results in the field of public health. Combating antibiotic resistance is among the areas covered by this approach. …”

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Learn About the “One Health” Concept

May 17, 2021


Season 2 Episode 1 | 25m 56s |Video has closed captioning.

One Health is a concept that connects the health of animals, people, and the environment. Each aspect is equal, important, and delicately intertwined. In this episode, Wildlife Center veterinary and rehabilitation staff, along with public health officials, explain One Health concepts and challenges, and highlight how we can work together for the optimal health of all.


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Pandemic protection: ‘animal-disease detectives’ safeguarding health

May 14, 2021

14 May 2021

“A University of Queensland researcher is helping train ‘animal-disease detectives’ to protect animals and humans from the threat of future pandemics. …

… The APCOVE project is built upon the One Health approach, a collaborative effort to work across different sectors, such as public health, animal health, plant health and the environment, and on a local, national, and global level, to attain optimal health for people, animals and our environment.”

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World Veterinary Association (WVA) Position on Zoonoses Emergence in Relation to Wildlife Disruption and Trade

May 13, 2021


” … Members are encouraged to engage in multisectoral-multidisciplinary, One Health networks and support the global initiative on Preventing the Next Pandemic. …”

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Master of Science in Environmental Health Sciences DEOHS – University of Washington (USA): Why study One Health?

May 11, 2021

“ … Why study One Health?

One Health is a transdisciplinary approach to health issues affecting humans, animals and the rapidly changing environments we share. One Health specialists look at a range of issues—from emerging zoonotic diseases and antimicrobial resistance to climate change and food production—through the lens of creating a healthy coexistence between humans and animals in sustainable ecosystems.

Our UW Center for One Health Research, part of DEOHS, offers traineeships for the Occupational Health at the Human-Animal Interface training program, funded by the National Institute for Occupational Safety and Health. …”

Our faculty and research


Our study looking into whether pets can get COVID-19 aims to help people with good preventive practices to avoid transmission between people and animals.

*Dr. Peter Rabinowitz,
DEOHS Professor and Director, UW Center for One Health Research
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*Member One Health Initiative Advisory Board

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To Prevent Future Pandemics, Start by Protecting Nature

May 10, 2021

” … Given these linkages, pandemic prevention efforts must be grounded in a “One Health” approach that recognizes the intimate interconnections among human, animal and environmental health. …”

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The Coming Pandemic: Preparing for the Future: Infectious Disease Special Edition

May 7, 2021

… the authors emphasized “the wisdom of adopting a One Health approach,” … (Lancet 2021 Mar 9.

“ … Because many pandemics are zoonotic, the authors emphasized “the wisdom of adopting a One Health approach,” which recognizes that the health of people is closely linked to the health of animals and their shared environment. …”

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