Collection of triatomines from sylvatic habitats by a Trypanosoma cruzi-infected scent detection dog in Texas, USA.

BACKGROUND: Triatomine insects, vectors of the etiologic agent of Chagas disease (Trypanosoma cruzi), are challenging to locate in sylvatic habitats. Collection techniques used in the United States often rely on methods to intercept seasonally dispersing adults or on community scientists' encounters. Neither method is suited for detecting nest habitats likely to harbor triatomines, which is important for vector surveillance and control. Furthermore, manual inspection of suspected harborages is difficult and unlikely to reveal novel locations and host associations. Similar to a team that used a trained dog to detect sylvatic triatomines in Paraguay, we worked with a trained scent detection dog to detect triatomines in sylvatic locations across Texas. PRINCIPLE METHODOLOGY/FINDINGS: Ziza, a 3-year-old German Shorthaired Pointer previously naturally infected with T. cruzi, was trained to detect triatomines. Over the course of 6 weeks in the fall of 2017, the dog and her handler searched at 17 sites across Texas. The dog detected 60 triatomines at 6 sites; an additional 50 triatomines were contemporaneously collected at 1 of these sites and 2 additional sites without the assistance of the dog. Approximately 0.98 triatomines per hour were found when only humans were conducting searches; when working with the dog, approximately 1.71 triatomines per hour were found. In total, 3 adults and 107 nymphs of four species (Triatoma gerstaeckeri, Triatoma protracta, Triatoma sanguisuga, and Triatoma indictiva) were collected. PCR testing of a subset revealed T. cruzi infection, including DTUs TcI and TcIV, in 27% of nymphs (n = 103) and 66% of adults (n = 3). Bloodmeal analysis of a subset of triatomines (n = 5) revealed feeding on Virginia opossum (Didelphis virginiana), Southern plains woodrat (Neotoma micropus), and eastern cottontail (Sylvilagus floridanus). CONCLUSION/SIGNIFICANCE: A trained scent detection dog enhanced triatomine detections in sylvatic habitats. This approach is effective at detecting nidicolous triatomines. Control of sylvatic sources of triatomines is challenging, but this new knowledge of specific sylvatic habitats and key hosts may reveal opportunities for novel vector control methods to block the transmission of T. cruzi to humans and domestic animals.

Clinical and epidemiologic features of SARS-CoV-2 in dogs and cats compiled through national surveillance in the United States.

OBJECTIVE: 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.

Novel Regioselective Approach to Cyclize Phage-Displayed Peptides in Combination with Epitope-Directed Selection to Identify a Potent Neutralizing Macrocyclic Peptide for SARS-CoV-2.

Using the regioselective cyanobenzothiazole condensation reaction with an N-terminal cysteine and the chloroacetamide reaction with an internal cysteine, a phage-displayed macrocyclic 12-mer peptide library was constructed and subsequently validated. Using this library in combination with iterative selections against two epitopes from the receptor binding domain (RBD) of the novel severe acute respiratory syndrome virus 2 (SARS-CoV-2) Spike protein, macrocyclic peptides that strongly inhibit the interaction between the Spike RBD and angiotensin-converting enzyme 2 (ACE2), the human host receptor of SARS-CoV-2, were identified. The two epitopes were used instead of the Spike RBD to avoid selection of nonproductive macrocyclic peptides that bind RBD but do not directly inhibit its interactions with ACE2. Antiviral tests against SARS-CoV-2 showed that one macrocyclic peptide is highly potent against viral reproduction in Vero E6 cells with an EC50 value of 3.1 µM. The AlphaLISA-detected IC50 value for this macrocyclic peptide was 0.3 µM. The current study demonstrates that two kinetically controlled reactions toward N-terminal and internal cysteines, respectively, are highly effective in the construction of phage-displayed macrocyclic peptides, and the selection based on the SARS-CoV-2 Spike epitopes is a promising methodology in the identification of peptidyl antivirals.

SARS-CoV-2 Infections in a High-Risk Migratory Population Arriving to a Migrant House along the US-Mexico Border.

Few reports exist on the COVID-19 epidemiology of migrant populations. We tested 370 migratory individuals from ten countries arriving at a migrant house along the US-Mexico border based on a rapid assay detecting SARS-CoV-2 antigen. Fifty-six were positive, for a prevalence of 15.1% (95%-CIs of 11.8-19.2%). Only 21 positive persons presented signs or symptoms associated with the infection (95%-CIs = 25-49%). Most (51.7%) positive migrants arrived in the previous two days before being tested, indicating that the virus infection was acquired during their transit. Out of the total of 56 positive individuals, 37.5% were from El Salvador, 33.9% from Honduras, and 21.4% from Guatemala. This study suggests that vulnerable populations traveling from countries in Latin America and seeking residence in the US are high-risk individuals for exposure to SARS-CoV-2. The rapid antigen COVID-19 testing on arrival at the migrant house, and subsequent 10-day quarantine, was a critical step to help minimize further transmission. Therefore, the present study demonstrates that public health services provided to migratory and vulnerable populations are necessary for pandemic control.

Persistence of SARS-CoV-2 neutralizing antibodies longer than 13 months in naturally infected, captive white-tailed deer (Odocoileus virginianus), Texas.

After identifying a captive herd of white-tailed deer in central Texas with >94% seroprevalence with SARS-CoV-2 neutralizing antibodies in September 2021, we worked retrospectively through archived serum samples of 21 deer and detected seroconversion of all animals between December 2020 and January 2021. We then collected prospective samples to conclude that the duration of persistence of neutralizing antibodies is at least 13 months for 19 (90.5%) of the animals, with two animals converting to seronegative after six and eight months. Antibody titres generally waned over this time frame, but three deer had a temporary 4- to 8-fold increases in plaque reduction neutralization test titres over a month after seroconversion; anamnestic response cannot be ruled out.

No Evidence of SARS-CoV-2 Among Flies or Cockroaches in Households Where COVID-19 Positive Cases Resided.

Flies and other arthropods mechanically transmit multiple pathogens and a recent experimental study demonstrated house flies, Musca domestica L. (Diptera: Muscidae), can mechanically transmit SARS-CoV-2. The purpose of this study was to explore the possibility of mechanical transmission of SARS-CoV-2 by domestic insects and their potential as a xenosurveillance tool for detection of the virus. Flies were trapped in homes where at least one confirmed human COVID-19 case(s) resided using sticky and liquid-baited fly traps placed inside and outside the home in the Texas counties of Brazos, Bell, and Montgomery, from June to September 2020. Flies from sticky traps were identified, pooled by taxa, homogenized, and tested for the presence of SARS-CoV-2 RNA using quantitative reverse transcription PCR (RT-qPCR). Liquid traps were drained, and the collected fluid similarly tested after RNA concentration. We processed the contents of 133 insect traps from 40 homes, which contained over 1,345 individual insects of 11 different Diptera families and Blattodea. These individuals were grouped into 243 pools, and all tested negative for SARS-CoV-2 RNA. Fourteen traps in seven homes were deployed on the day that cat or dog samples tested positive for SARS-CoV-2 RNA by nasal, oral, body, or rectal samples. This study presents evidence that biting and nonbiting flies and cockroaches (Blattodea) are not likely to contribute to mechanical transmission of SARS-CoV-2 or be useful in xenosurveillance for SARS-CoV-2.

High Seroprevalence of SARS-CoV-2 in White-Tailed Deer (Odocoileus virginianus) at One of Three Captive Cervid Facilities in Texas.

Free-ranging white-tailed deer (Odocoileus virginianus) across the United States are increasingly recognized for infection and transmission of SARS-CoV-2. Through a cross-sectional study of 80 deer at three captive cervid facilities in central and southern Texas, we provide evidence of 34 of 36 (94.4%) white-tailed deer at a single captive cervid facility seropositive for SARS-CoV-2 by neutralization assay (PRNT90), with endpoint titers as high as 1,280. In contrast, all tested white-tailed deer and axis deer (Axis axis) at two other captive cervid facilities were seronegative, and SARS-CoV-2 RNA was not detected in respiratory swabs from deer at any of the three facilities. These data support transmission among captive deer that cannot be explained by human contact for each infected animal, as only a subset of the seropositive does had direct human contact. The facility seroprevalence was more than double of that reported from wild deer, suggesting that the confined environment may facilitate transmission. Further exploration of captive cervids and other managed animals for their role in the epizootiology of SARS-CoV-2 is critical for understanding impacts on animal health and the potential for spillback transmission to humans or other animal taxa. IMPORTANCE As SARS-CoV-2 vaccine coverage of the human population increases and variants of concern continue to emerge, identification of the epidemiologic importance of animal virus reservoirs is critical. We found that nearly all (94.4%) of the captive white-tailed deer at a cervid facility in central Texas had neutralizing antibodies for SARS-CoV-2. This seroprevalence is over double than that which has been reported from free-ranging deer from other regions of the United States. Horizontal transmission among deer may be facilitated in confinement. Tracking new infections among wild and confined deer is critical for understanding the importance of animal reservoirs for both veterinary and human health.

SARS-CoV-2 Infections and Viral Isolations among Serially Tested Cats and Dogs in Households with Infected Owners in Texas, USA.

Understanding the ecological and epidemiological roles of pets in the transmission of SARS-CoV-2 is critical for animal and human health, identifying household reservoirs, and predicting the potential enzootic maintenance of the virus. We conducted a longitudinal household transmission study of 76 dogs and cats living with at least one SARS-CoV-2-infected human in Texas and found that 17 pets from 25.6% of 39 households met the national case definition for SARS-CoV-2 infections in animals. This includes three out of seventeen (17.6%) cats and one out of fifty-nine (1.7%) dogs that were positive by RT-PCR and sequencing, with the virus successfully isolated from the respiratory swabs of one cat and one dog. Whole-genome sequences of SARS-CoV-2 obtained from all four PCR-positive animals were unique variants grouping with genomes circulating among people with COVID-19 in Texas. Re-sampling showed persistence of viral RNA for at least 25 d-post initial test. Additionally, seven out of sixteen (43.8%) cats and seven out of fifty-nine (11.9%) dogs harbored SARS-CoV-2 neutralizing antibodies upon initial sampling, with relatively stable or increasing titers over the 2-3 months of follow-up and no evidence of seroreversion. The majority (82.4%) of infected pets were asymptomatic. 'Reverse zoonotic' transmission of SARS-CoV-2 from infected people to animals may occur more frequently than recognized.

SARS-CoV-2 B.1.1.7 variant of concern detected in a pet dog and cat after exposure to a person with COVID-19, USA.

As part of a longitudinal household transmission study of pets living with persons with COVID-19 in Texas, two pets were confirmed to be infected with the SARS-CoV-2 B.1.1.7 variant of concern (VOC). The pets were a dog and a cat from the same household, sampled two days after their owner tested positive for COVID-19. The oral, nasal and fur swabs for both pets tested positive for SARS-CoV-2 by qRT-PCR and consensus whole-genome sequences from the dog and cat were 100% identical and matched the B.1.1.7 VOC. Virus was isolated from the cat's nasal swab. One month after initial detection of infection, the pets were re-tested twice at which time only the fur swabs (both pets) and oral swab (dog only) remained positive, and neutralizing antibodies for SARS-CoV-2 were present in both animals. Sneezing by both pets was noted by the owner in the weeks between initial and follow-up testing. This study documents the first detection of B.1.1.7. in companion animals in the United States, and the first genome recovery and isolation of B.1.1.7 variant of concern globally in any animal.