SARS-CoV-2 Rapid Antigen Testing of Symptomatic and Asymptomatic Individuals on the University of Arizona Campus.

SARS-CoV-2, the cause of COVID19, has caused a pandemic that has infected more than 80 M and killed more than 1.6 M persons worldwide. In the US as of December 2020, it has infected more than 32 M people while causing more than 570,000 deaths. As the pandemic persists, there has been a public demand to reopen schools and university campuses. To consider these demands, it is necessary to rapidly identify those individuals infected with the virus and isolate them so that disease transmission can be stopped. In the present study, we examined the sensitivity of the Quidel Rapid Antigen test for use in screening both symptomatic and asymptomatic individuals at the University of Arizona from June to August 2020. A total of 885 symptomatic and 1551 asymptomatic subjects were assessed by antigen testing and real-time PCR testing. The sensitivity of the test for both symptomatic and asymptomatic persons was between 82 and 90%, with some caveats.

Prevalence of coccidioidomycosis in cystic fibrosis patients residing in Southern Arizona.

Sparse data exists about patients with cystic fibrosis (CF) and their risk of contracting coccidioidiomycosis or Valley Fever, which is highly endemic in southern Arizona. A retrospective review of medical records of 79 adult CF patients residing in Arizona was performed. Two cases only of coccidioidomycosis were documented between in the 790 patient years. However, false-positive serologies were found in 15 patients. This 10-year retrospective review of 79 adult CF patients found that there was a lower prevalence of coccidioidomycosis in CF patients compared to that of the general population of the area. LAY SUMMARY: Patients with cystic fibrosis (CF) suffer from chronic lung infection. Little is known about CF and fungal infection. Coccidioidomycosis is a fungal infection common in Arizona and this study shows a lower infection rate from Coccidioidomycosis in CF patients compared to the general population.

Orthogonal SARS-CoV-2 Serological Assays Enable Surveillance of Low-Prevalence Communities and Reveal Durable Humoral Immunity.

We conducted a serological study to define correlates of immunity against SARS-CoV-2. Compared to those with mild coronavirus disease 2019 (COVID-19) cases, individuals with severe disease exhibited elevated virus-neutralizing titers and antibodies against the nucleocapsid (N) and the receptor binding domain (RBD) of the spike protein. Age and sex played lesser roles. All cases, including asymptomatic individuals, seroconverted by 2 weeks after PCR confirmation. Spike RBD and S2 and neutralizing antibodies remained detectable through 5-7 months after onset, whereas α-N titers diminished. Testing 5,882 members of the local community revealed only 1 sample with seroreactivity to both RBD and S2 that lacked neutralizing antibodies. This fidelity could not be achieved with either RBD or S2 alone. Thus, inclusion of multiple independent assays improved the accuracy of antibody tests in low-seroprevalence communities and revealed differences in antibody kinetics depending on the antigen. We conclude that neutralizing antibodies are stably produced for at least 5-7 months after SARS-CoV-2 infection.

Detection, prevalence, and duration of humoral responses to SARS-CoV-2 under conditions of limited population exposure.

We conducted an extensive serological study to quantify population-level exposure and define correlates of immunity against SARS-CoV-2. We found that relative to mild COVID-19 cases, individuals with severe disease exhibited elevated authentic virus-neutralizing titers and antibody levels against nucleocapsid (N) and the receptor binding domain (RBD) and the S2 region of spike protein. Unlike disease severity, age and sex played lesser roles in serological responses. All cases, including asymptomatic individuals, seroconverted by 2 weeks post-PCR confirmation. RBD- and S2-specific and neutralizing antibody titers remained elevated and stable for at least 2-3 months post-onset, whereas those against N were more variable with rapid declines in many samples. Testing of 5882 self-recruited members of the local community demonstrated that 1.24% of individuals showed antibody reactivity to RBD. However, 18% (13/73) of these putative seropositive samples failed to neutralize authentic SARS-CoV-2 virus. Each of the neutralizing, but only 1 of the non-neutralizing samples, also displayed potent reactivity to S2. Thus, inclusion of multiple independent assays markedly improved the accuracy of antibody tests in low seroprevalence communities and revealed differences in antibody kinetics depending on the viral antigen. In contrast to other reports, we conclude that immunity is durable for at least several months after SARS-CoV-2 infection.

Unconscious Woman in Shock and Covered with Ants Pulled from an Abandoned Automobile.

BACKGROUND: A middle-aged woman was taken from an abandoned automobile unconscious and covered with ants in Tucson, Arizona. When hospitalized in July 2018, she had an extensive papular-pustular skin eruption on her abdomen and thigh and disseminated intravascular coagulation. She was stung innumerable times by native golden fire ants (Solenopsis aurea) while sleeping in the vehicle. The large amount of venom injected by stings into this individual may have triggered dissemnated intravascualar coagulation because the venom contains powerful hemolytic factors. METHODS: The patient history is presented and ants were captured and identified. RESULTS: Clinical findings of fire ant stings are presented and the importance of recognizing the distinctive skin lesions that occur is emphasized. Stings of the red imported fire ant, Solenopsis invicta, and the black imported fire ant, Solenopsis richteri, cause skin lesions recognized by physicians and victims alike in the southern and southeastern United States. Native fire ant stings are documented much less often. However, there is significant cross-reactivity among the venoms of Solenopsis species. CONCLUSION: It is important for clinicians to recognize the characteristic skin lesions of fire ant envenomation as fire ant populations are expanding and they sting millions of people each year.