Community-Based Testing for COVID-19 in a Low-Prevalence, Rural Area: Documentation of Logistics and Practical Aspects of Testing

INTRODUCTION

Testing and mitigation strategies for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection often focus on high-prevalence, urban communities, leaving low-prevalence rural areas without specific strategies to maintain the health and safety of their populations. We evaluated a cost-effective strategy for SARS-CoV-2 testing to determine point prevalence in a rural community with a generally low prevalence of infection.

METHODS

We voluntarily tested asymptomatic clinic employees and conducted 2 community SARS-CoV-2 testing events in Cashton, Wisconsin, that included testing for asymptomatic persons. We also partnered with local clinics and public health departments to conduct weekly drive-up clinics for asymptomatic, high-risk persons identified through enhanced contact tracing. This was possible as testing capacity in Wisconsin never reached its maximum, and we continued symptomatic testing through our clinic.

RESULTS

We tested 61 employees, 268 individuals at 2 community events, 36 high-risk asymptomatic people at drive-up clinic events, and 128 symptomatic people within our clinic. We observed 1 positive result in asymptomatic people and 5 positive results in symptomatic patients, confirming the low prevalence in our area.

CONCLUSIONS

Our testing events confirmed a low prevalence of SARS-CoV-2 infection, providing prevalence information to local businesses and schools. We reinforced our partnership with local public health departments to facilitate enhanced contact tracing and test asymptomatic persons, and we provided a service to asymptomatic persons requiring testing for travel, school, or work. Local businesses and community members appreciated the services and expressed relief for point-in-time testing results during a period of stress and uncertainty.

First report of sacbrood virus in honey bee (Apis mellifera) colonies in Brazil

Sacbrood disease, an affliction of honey bees (Apis mellifera) characterized by brood that fails to pupate and subsequently dies, is an important threat to honey bee health. The disease is caused by the sacbrood virus (SBV), a positive-, single-stranded RNA virus in the order Picornavirales. Because of the economic importance of honey bees for both pollination and honey production, it is vital to understand and monitor the spread of viruses such as SBV. This virus has been found in many places across the globe, including recently in some South American countries, and it is likely that it will continue to spread. We performed a preliminary study to search for SBV in two apiaries of Africanized honey bees in the State of São Paulo, Brazil, using RT-PCR and Sanger sequencing and found the first evidence of SBV in honey bee colonies in Brazil. The virus was detected in larvae, foraging and nurse bees from two colonies, one of which had symptoms of sacbrood disease, at the beginning of the winter season in June 2011. No SBV was found in samples from nine other nearby colonies.

Polyamino acid enhancement of bacterial phagocytosis by human polymorphonuclear leukocytes and peritoneal macrophages

Cationic polyamino acids are known to enhance a variety of cell-cell interactions by virtue of their ability to alter electrostatic forces of cell surfaces. In this study, the effect of polyamino acids on phagocytosis of 3H-labeled bacteria by human polymorphonuclear leukocytes (PMNs) and peritoneal macrophages was investigated. Negatively charged and neutral polyamino acids did not influence phagocytosis of unopsonized Staphylococcus epidermidis, whereas protamine, poly-L-arginine, and poly-L-lysine stimulated phagocytosis in a dose-dependent manner. At 50 micrograms/ml, greater than 30% uptake by PMNs was seen with each of these cationic polyamino acids. Although cationic polyamino acids promoted PMN and peritoneal macrophage phagocytosis of unopsonized S. epidermidis, Staphylococcus aureus M (encapsulated) and M variant (unencapsulated), and Escherichia coli J5, little effect was seen with the parent E. coli O111:B4 or a serotype O222:H16 strain. Pretreatment of bacteria and phagocytes separately demonstrated that the phagocytosis-promoting property of polyamino acids is manifest predominantly on the bacteria. Bacteria pretreated with cationic polyamino acids also elicited a PMN chemiluminescent response, and PMN-associated bacteria were killed, as determined by a fluorochrome microassay. Thus, cationic polyamino acids promote the phagocytosis and killing of many but not all bacterial strains, and in this respect polyamino acids function as opsonins.

Human peritoneal macrophage cytotoxicity mediated by cytophilic IgG

Cells of the human mononuclear phagocyte system have recently been shown to possess cytophilic IgG molecules that promote phagocytosis of staphylococci bearing cell-wall protein A. In the present study, the possible mediation of a cytotoxic response to 51Cr-labeled sheep erythrocytes coated with protein A by cytophilic antibodies on human peritoneal macrophages was evaluated. The target cells were readily lysed by peritoneal macrophages. Cytotoxicity was blocked by pretreatment of macrophages with soluble protein or with anti-Fc F(ab')2 fragments. In contrast, cytotoxicity was not affected by cytochalasin B; this finding suggests that cytolysis is an extracellular event. Perturbation of cytophilic IgG with particle-bound protein A elicited a chemiluminescent response from peritoneal macrophages; however, experiments with scavengers of reactive oxygen species indicated that toxic oxygen radicals may not be required for cytotoxicity. The results indicate that cytophilic antibody-mediated cytotoxicity may contribute to cellular injury as well as host-defense aspects of the inflammatory process.