Rebecca Fischer
· Associate ProfessorVerifiedTexas A&M University · Epidemiology and Biostatistics
Active 1943–2026
About
Rebecca Fischer, PhD, MPH, DTMH, is an Associate Professor in Epidemiology & Biostatistics at the School of Public Health, Texas A&M University. Her research interests include the epidemiology of tropical diseases, epidemic investigations, global health, risk factors for infectious diseases, clinical disease characterization in emerging tropical diseases, infectious disease diagnosis and surveillance in resource-limited settings, and utilizing trained students for epidemiologic surge capacity needs. Fischer holds a Diploma in Tropical Medicine & Hygiene from the Gorgas Memorial Institute of Tropical and Preventive Medicine (2018), completed postdoctoral training in Tropical Medicine at Baylor College of Medicine (2018), earned a PhD in Field Epidemiology from the University of Texas Health Science Center School of Public Health (2014), and an MPH in Infectious Disease Epidemiology from the same institution (2009). She also holds a BS in Biology: Ecology, Evolution & Conservation from the University of Texas at Austin (1998). Her professional background and research focus are centered on infectious disease epidemiology, outbreak investigation, and global health, with a particular emphasis on tropical diseases and epidemiologic response in resource-limited settings.
Research topics
- Medicine
- Internal medicine
- Virology
- Computer Science
- Veterinary medicine
- Biology
- Environmental health
- Geography
- Mathematics
- Physical therapy
- Social psychology
- Statistics
- Telecommunications
- Psychology
- Family medicine
- Immunology
- Archaeology
- Econometrics
Selected publications
One Health · 2026-03-03
articleOpen accessHouseholds where people have COVID-19 are high-risk environments for companion animals to become infected by SARS-CoV-2. We sampled 579 pets from 281 households with one or more laboratory-confirmed persons with COVID-19 in central Texas from June 2020 to May 2021. Nineteen out of 396 (4.8%) dogs and 21 out of 157 (13.4%) cats were positive for SARS-CoV-2 by RT-qPCR. Additionally, 95/382 (25%) dogs and 52/146 (36%) cats harbored SARS-CoV-2 neutralizing antibodies. Twenty-six companion animals of ten other species were negative. Overall, 164 (29%) pets were positive for SARS-CoV-2 by molecular and/or serological tests; a total of 110 (39%) out of 281 households had at least one animal with active or past SARS-CoV-2 infection. Cats were more likely to be infected by SARS-CoV-2 and had higher endpoint antibody titers than dogs. We detected 11 SARS-CoV-2 lineages and isolated five of them from dogs and cats, including the B.1.234 lineage that was isolated from a cat a few weeks after the first detection in humans in the United States. Detection of SARS-CoV-2 RNA decreased by 10% per additional day post COVID-19 diagnosis of the human case in the household for both dogs and cats, whereas seropositivity odds increased with each additional day. Human-pet interactions associated with a higher risk of infection in dogs and cats included sleeping in the same room as an infected person, living with multiple infected persons, and sharing food with people. The frequency of clinical signs in pets with active infections did not differ from uninfected ones, suggesting that not all reported signs are attributed to SARS-CoV-2 infection. Characterizing animal infections using active SARS-CoV-2 surveillance in pets at risk of infection may aid in One Health pandemic prevention, response, and management.
Research Square · 2026-02-24
preprintOpen accessSenior authorScientific Reports · 2026-05-15
articleOpen accessSenior authorGiardia duodenalis is a protozoal parasite that infects a wide range of animal hosts including dogs and humans. Although social determinants of health (SDOH) are well characterized in human disease, their role in shaping animal health outcomes remains poorly understood. This ecological study, guided by One Health principles, evaluated temporospatial trends in canine Giardia infection in Texas and assessed associations with county-level human socioeconomic indicators. Veterinary diagnostic test results from commercial laboratories during 2012-2022 were analyzed to characterize temporal and geographic variation in test positivity. Negative binomial regression models were used to examine associations between Giardia positivity and county-level measures of poverty, unemployment, income, educational attainment, and veterinary care accessibility scores (VCAS). Cumulatively, 4.6% of canine tests were positive at the state level, with substantial county-level variation (median 4.6% [range 0.6-12.1%]; mean 4.9% [CI 4.1-5.8%]). Higher positivity was associated with limited veterinary care access (uPR 2.0 [CI 1.4-3.0], P value < 0.001) and a lower proportion of college graduates (uPR 1.6 [CI 1.2-2.1], P value < 0.001). Temporal increases in positivity were observed in Cameron County and Lubbock County, whereas decreases were noted in El Paso County and Parker County. These findings suggest that socioeconomic factors related to veterinary access and education are associated with canine Giardia infection risk and may help identify regions where targeted interventions are warranted. However, further studies are needed to elucidate the underlying mechanisms and zoonotic implications.
bioRxiv (Cold Spring Harbor Laboratory) · 2025-02-04 · 4 citations
preprintOpen accessAbstract Households where people have COVID-19 are high risk environments for companion animals that are susceptible to SARS-CoV-2. We sampled 579 pets from 281 households with one or more laboratory-confirmed person with COVID-19 in central Texas from June 2020 to May 2021. Nineteen out of 396 (4.8%) dogs and 21 out of 157 (13.4%) cats were positive for SARS-CoV-2 by RT-qPCR. Additionally, 95/382 (25%) dogs and 52/146 (36%) cats harbored SARS-CoV-2 neutralizing antibodies. Twenty-six companion animals of ten other species were negative. Overall, 164 (29%) pets were positive for SARS-CoV-2 by molecular and/or serological tests; a total of 110 (39%) out of 281 households had at least one animal with active or past SARS-CoV-2 infection. Cats were more likely to be infected by SARS-CoV-2 and had higher endpoint antibody titers than dogs. Through viral isolation from a subset of respiratory swabs, we documented 6 different lineages in dogs and cats, including the B.1.1 lineage in a cat one month prior to the first known human case in the country. We observed animal and human-pet interaction factors associated with higher risk of infection for dogs and cats, such as days after COVID-19 diagnosis and sharing food. Frequency of clinical signs of disease reported by owners of pets with active infections did not differ from uninfected ones, suggesting that not all reported signs are attributed to SARS-CoV-2 infection. Characterizing animal infections using active SARS-CoV-2 surveillance in pets at risk of infection may aid in One Health pandemic prevention, response, and management.
mSphere · 2025-07-02
articleOpen accessABSTRACT Monitoring the zoonotic potential of emerging SARS-CoV-2 variants in animals is a critical tool to protect public health. We conducted a longitudinal study in 47 households reporting people with COVID-19 in Texas from January to July 2022, during the first Omicron wave. We evaluated 105 people and 100 of their companion animals for SARS-CoV-2 infection at three sequential sampling events, starting 0–5 days after the first reported diagnosis of COVID-19 in the house. SARS-CoV-2 RNA was detected in 68% of people from 43 households; 95.5% of people had antibodies to SARS-CoV-2. Dogs were the only animal species positive by RT-qPCR (5.4%; 3/55), and their viral loads were consistently lower compared with those from household members. Additionally, infected dogs did not yield infectious virus. Clusters of Omicron BA.1.1, BA.2.3.4, and BA.5.1.1 in people, dogs, and a dog food bowl confirmed human-to-dog transmission within households, with no evidence of onward transmission from the infected dogs. Eleven dogs ( n = 55) and two cats ( n = 26) had neutralizing antibodies against SARS-CoV-2. Overall, infection was not associated with clinical signs in pets; only two animals that tested negative for SARS-CoV-2 were reported to be sick. Nearly one-third (30.2%) of households with active COVID-19 had pets exposed to SARS-CoV-2, similar to our pre-Omicron studies; however, the incidence of infection in cats was lower compared with pre-Omicron. These differences suggest that the zoonotic transmission dynamics in households may differ based on variants. IMPORTANCE SARS-CoV-2 infects a broad diversity of mammals, with companion dogs and cats at risk of infection via close contact with infectious owners. Longitudinal studies sampling pets and their owners over time are essential to understanding within-household SARS-CoV-2 transmission dynamics. Our repeated sampling in households with people reporting COVID-19 found that 68% of the people in 43 households had active SARS-CoV-2 infection during at least one of the three sampling events. Although none of the 27 cats were positive, 3/55 dogs had active infections. Household clusters of three different Omicron subvariants were involved in these human-to-dog transmission events, and our data suggest reduced infection in pets during Omicron transmission compared with pre-Omicron waves. Protecting pets from SARS-CoV-2 infection remains important, as viral evolution can be accompanied by changes in the infectiousness of different hosts.
medRxiv · 2025-03-04 · 1 citations
preprintOpen accessSenior authorABSTRACT Introduction End stage kidney disease (ESKD) affects an estimated 5500 persons living in the United States without legal residency documentation. One likely, but underappreciated cause of ESKD in the Hispanic migrant population, is chronic kidney disease of unknown etiology (CKDu). CKDu is an interstitial nephritis that disproportionately affects young adult agricultural workers in Central America who lack traditional risk factors for kidney disease. In underserved populations, such as those at risk for CKDu, substantial barriers to optimal kidney care translate to poorer health outcomes and widening health disparities. Without funding for non-emergent healthcare, this underserved population, often only have access to hemodialysis (HD) once a life-threatening condition occurs. Despite the presence of a migrant population from CKDu endemic countries and anecdotes of its presence, CKDu has very rarely been directly investigated or documented in the US. We undertook this study to establish the existence of CKDu in the United States and to characterize CKDu as a cause of ESKD in patients accessing emergent HD. Methods In a retrospective cross-sectional study among patients receiving emergent HD in Texas, we analyzed medical record data from a large, county hospital. We ascertained cause of ESKD and underlying hypertension and diabetes and compared these proportions to data on patients on maintenance HD from the US Renal Data System (USRDS). Undocumented immigrants are largely excluded from the USRDS, as with many health statistics databases in the US. We identified patients whose clinicians had indicated CKDu as a diagnosis and classified others as having suspected CKDu or possible CKDu based on clinically informed criteria. Results We identified 346 patients with ESKD requiring emergent HD (2012-2015), who were younger than patients in the USRDS (median age 52 yrs vs. 61 yrs, p <0.001), had more comorbid diabetes (60% vs. 47%, p <0.001), and more often had an unknown cause of ESKD (16% vs. 4%, p<0.001). Patients requiring emergent HD also had less frequent arteriovenous access (12% vs. 82%, p<0.001). ESKD attributed to diabetes and/or hypertension accounted for only 67% of emergent HD patients, compared to 81% of USRDS patients (p<0.001). 14% of the patients on emergent HD died during the study period. Four patients had been clinically diagnosed with CKDu, while we classified 14 with suspected CKDu and 40 with possible CKDu, for a total of 58 patients (17%) with potentially CKDu-related ESKD. Conclusion Our analysis suggests that up to 17% of patients in this population utilizing emergent HD had CKDu-related ESKD, suggesting that CKDu is likely underdiagnosed in the US. Further, patients receiving emergent HD were younger but were at higher risk of infection or complication than patients receiving scheduled, maintenance HD. Understanding CKDu and improving access to scheduled dialysis for migrants without legal residency documentation should be prioritized to reduce stress on the healthcare system and improve health among vulnerable populations in the US.
Lupus Science & Medicine · 2025-01-01 · 1 citations
articleOpen accessOBJECTIVES: The aim of our work was to identify specific patterns in clinical features and nailfold capillary changes that may help in screening for pulmonary arterial hypertension (PAH) in patients with systemic lupus erythematosus (SLE). METHODS: We identified patients with SLE and type I PAH (n=20) without other connective tissue diseases and collected demographic, clinical and laboratory features. We selected as controls patients with SLE who underwent cardiopulmonary screening to exclude PAH (n=87): we collected demographic, clinical and laboratory features and performed nailfold videocapillaroscopy (NVC). RESULTS: All patients with SLE-PAH were women; age and disease duration were not different from patients with SLE without PAH. Lupus anticoagulant (LAC)+and anti-ribonucleoprotein (RNP)+were more prevalent in patients with SLE-PAH (respectively, PAH 45.0% vs no-PAH 20.5%, p=0.042; PAH 45.0% vs no-PAH 19.5%, p=0.035). No differences were observed for anti-Sm, anti-Ro, anti-La and anti-cardiolipin and anti-beta2GPI antibodies. Among clinical features, mucocutaneous and central nervous system involvement were more prevalent in patients with SLE-PAH than in SLE controls (respectively, PAH 65.0% vs no-PAH 34.5%, p=0.024; PAH 25.0% vs no-PAH 8.0%, p=0.046). Raynaud's phenomenon (RP) was more prevalent in patients with SLE-PAH than in SLE controls (PAH 60.0% vs no-PAH 13.8%, p<0.001). RP was a predictor of PAH in patients with SLE (OR 3.8 (0.9-14.8)). We performed NVC on nine patients with PAH and on controls: we observed a significantly higher prevalence of scleroderma pattern at NVC in SLE-PAH than controls (PAH 66.7% vs no-PAH 9.2%, p<0.001). Patients with SLE-PAH showed a lower number of capillary density and a higher frequency of giant capillaries. CONCLUSIONS: Our data showed that LAC+, RNP+, RP and a scleroderma pattern at NVC was indicative for patients with SLE-PAH. Our results pointed to generalised microvascular involvement and a hypercoagulation state in patients with SLE-PAH. The variables we identified could be used to implement a screening algorithm to identify patients with SLE at risk of developing PAH.
Persistence of dengue serotype 2 viral RNA in blood cells of a returned traveler with dengue fever
Travel Medicine and Infectious Disease · 2024-03-05 · 3 citations
articleOpen access1st authorCorrespondingDengue virus (DENV) is one of the most significant vector-borne pathogens worldwide. In this report, we describe clinical features and laboratory detection of dengue in a 45-year-old traveler to Nicaragua on return home to the United States in 2019. Clinical presentation was mild, with rash, headache, and fatigue, with only low-grade transient fever. Infection dynamics were documented by serology and PCR of serially collected body fluids. DENV serotype 2 was detected in whole blood 1 day after symptoms emerged, with viral RNA isolated to the red cell fraction, and remained detectable through day 89. DENV-2 RNA was detected in serum only on day 4, and IgM was undetectable on day 4 but evident by day 13. Viral RNA was also detected in urine. This report of DENV-2 RNA persistence in blood cells but only transient appearance in serum, supports the potential diagnostic value of whole blood over serum for PCR and opportunity of an expanded testing window. Informed testing approaches can improve diagnostic accuracy and inform strategies that preserve individual and public health.
Kidney International · 2023-12-29 · 7 citations
articleOpen accessJournal of the American Veterinary Medical Association · 2023-01-03 · 21 citations
articleOpen accessOBJECTIVE: To characterize clinical and epidemiologic features of SARS-CoV-2 in companion animals detected through both passive and active surveillance in the US. ANIMALS: 204 companion animals (109 cats, 95 dogs) across 33 states with confirmed SARS-CoV-2 infections between March 2020 and December 2021. PROCEDURES: Public health officials, animal health officials, and academic researchers investigating zoonotic SARS-CoV-2 transmission events reported clinical, laboratory, and epidemiologic information through a standardized One Health surveillance process developed by the CDC and partners. RESULTS: Among dogs and cats identified through passive surveillance, 94% (n = 87) had reported exposure to a person with COVID-19 before infection. Clinical signs of illness were present in 74% of pets identified through passive surveillance and 27% of pets identified through active surveillance. Duration of illness in pets averaged 15 days in cats and 12 days in dogs. The average time between human and pet onset of illness was 10 days. Viral nucleic acid was first detected at 3 days after exposure in both cats and dogs. Antibodies were detected starting 5 days after exposure, and titers were highest at 9 days in cats and 14 days in dogs. CLINICAL RELEVANCE: Results of the present study supported that cats and dogs primarily become infected with SARS-CoV-2 following exposure to a person with COVID-19, most often their owners. Case investigation and surveillance that include both people and animals are necessary to understand transmission dynamics and viral evolution of zoonotic diseases like SARS-CoV-2.
Recent grants
Frequent coauthors
- 32 shared
Kristy O. Murray
Emory University
- 21 shared
Edward Davila
Texas A&M University
- 21 shared
Lisa D. Auckland
Texas A&M University
- 21 shared
Sarah A. Hamer
Texas A&M University
- 19 shared
Gabriel L. Hamer
Texas A&M University
- 19 shared
Andrew P. Steenhoff
Children's Hospital of Philadelphia
- 18 shared
Italo B. Zecca
Texas A&M University
- 14 shared
Sreedhar Mandayam
The University of Texas MD Anderson Cancer Center
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