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Petersen, C. A.

Publications and source records attributed to Petersen, C. A..

3 recordsLinked to original sources
bioRxiv2021

Inclusion of environmentally themed search terms improved Elastic Net regression nowcasts of regional Lyme disease rates

Lyme disease is the most widely reported vector-borne disease in the United States. 95% of human cases are reported in the Northeast and upper Midwest. Human cases typically occur in the spring and summer months when an infected nymph Ixodid tick takes a blood meal. Current federal surveillance strategies report data on an annual basis, leading to nearly a year lag in national data reporting. These lags in reporting make it difficult for public health agencies to assess and plan for the current burden of Lyme disease. Implementation of a nowcasting model, using historical data to predict current trends, provides a means for public health agencies to evaluate current Lyme disease burden and make timely priority-based budgeting decisions. The objective of this study was to develop and compare the performance of nowcasting models using free data from Google Trends and Centers of Disease Control and Prevention surveillance reports for Lyme Disease. We developed two sets of elastic net models for five regions of the United States first using monthly proportional hit data from 21 disease symptoms and tick related terms and second using monthly proportional hit data from all terms identified via Google correlate plus 21 disease symptom and vector terms. Elastic net models using the larger term list were highly accurate (Root Mean Square Error: 0.74, Mean Absolute Error: 0.52, R2: 0.97) for four of the five regions of the United States. Including these more environmental terms improved accuracy 1.33-fold while reducing error 0.5-fold compared to predictions from models using disease symptom and vector terms alone. Models using Google data similar to this could help local and state public health agencies accurately monitor Lyme disease burden during times of reporting lag from federal public health reporting agencies.

systems biology↗
bioRxiv2021

Leishmania infantum xenodiagnosis from vertically infected dogs reveals significant skin tropism

BackgroundDogs are the primary reservoir for human visceral leishmaniasis due to Leishmania infantum. Phlebotomine sand flies maintain zoonotic transmission of parasites between dogs and humans. A subset of dogs is infected transplacentally during gestation, but at what stage of the clinical spectrum vertically infected dogs contribute to the infected sand fly pool is unknown. Methodology/Principal FindingsWe examined infectiousness of dogs vertically infected with L. infantum from multiple clinical states to the vector Lutzomyia longipalpis using xenodiagnosis and found that vertically infected dogs were infectious to sand flies at differing rates. Dogs with moderate disease showed significantly higher transmission to the vector than dogs with very mild or severe disease. We documented a substantial parasite burden in the skin of vertically infected dogs by RT-qPCR, despite these dogs not having received intradermal parasites via sand flies. There was a highly significant correlation between skin parasite burden at the feeding site and sand fly parasite uptake. This suggests dogs with high skin parasite burden contribute the most to the infected sand fly pool. Although skin parasite load and parasitemia correlated with one another, the average parasite number detected in skin was significantly higher compared to blood in matched subjects. Thus, dermal resident parasites were infectious to sand flies from dogs without detectable parasitemia. Conclusions/SignificanceTogether, our data implicate skin parasite burden and earlier clinical status as stronger indicators of outward transmission potential than blood parasite burden. Our studies of a population of dogs without vector transmission highlights the need to consider canine vertical transmission in surveillance and prevention strategies. AUTHOR SUMMARYSand flies transmit Leishmania parasites between infected dogs and humans leading to the life-threatening tropical disease Visceral Leishmaniasis (VL). Identifying which dogs transmit parasites well to sand flies is important to curb disease spread. The offspring of both dogs and humans can also be infected vertically while in utero. Despite this, the infectiousness of dogs that receive parasites in utero to sand flies has not been thoroughly investigated. Thus, we allowed sand flies to feed on a group of vertically infected dogs at varying stages of VL disease severity and measured sand fly parasite uptake. We found vertically infected dogs were readily able to transmit parasites to the sand flies. Dogs that were most infectious had moderate clinical disease and relatively high levels of parasite infection in their blood and skin. However, the level of skin infection was significantly higher than that observed in the blood, and the skin parasite load had the strongest correlation with sand fly parasite uptake. This implicates the skin may be an underappreciated driver of canine infectiousness to the sand fly vector. In addition, this work highlights that vertically infected dogs are very important parts of the transmission cycle and must be considered in all public health efforts addressing VL.

microbiology↗
bioRxiv2021

Maternal transfer of neutralizing antibodies to OspA after oral vaccination of the rodent reservoir

Lyme Disease presents unique challenges for public health efforts. We hypothesized that transfer of protective antibodies between mothers and offspring should occur after oral vaccination of C3H-HeN mice with E. coli overexpressing OspA. We present new evidence for maternal transfer of vaccine induced neutralizing anti-OspA IgG antibodies to mouse pups through ingestion of colostrum. Protective levels of OspA antibodies in pups were present from 2-5 weeks after birth and they persisted in some mice until 9 weeks of age. This was corroborated by detection of neutralizing antibodies in the serum of all pups at 2-3 weeks after birth and in some mice at 9 weeks of age. A clear association was found between robust antibody responses in mothers and the length of antibody persistence in the respective pups using a novel longitudinal Bayesian model. These factors are likely to impact the enzootic cycle of B. burgdorferi when reservoir targeted OspA-based vaccination interventions are implemented.

microbiology↗