Anaplasma phagocytophilum and Borrelia burgdorferi are both transmitted by Ixodes spp. and are associated with clinical illness in some infected dogs. This study evaluated canine antibody responses to the A. phagocytophilum p44 peptides APH-1 and APH-4 as well as the B. burgdorferi C6 peptide before and after doxycycline treatment. A total of eight dogs were infested with wild-caught I. scapularis for 1 week. Blood was collected prior to tick attachment and from Days 3-77 to 218-302 with doxycycline treatment beginning on Day 218. Blood was assayed for A. phagocytophilum DNA by PCR assay. Sera was assessed for antibodies by immunofluorescent antibody (IFA) test and ELISA. Anaplasma phagocytophilum DNA was amplified from blood of all dogs by Day 7. Antibodies to APH-4 were detected in serum as early as 14 days after tick exposure and six dogs had APH-4 antibodies detected 3-7 days before antibodies against APH-1. All dogs were seropositive for A. phagocytophilum from Days 218 to 302. Antibodies to B. burgdorferi were detected in 6/8 dogs beginning 21 days after I. scapularis infestation. Among the five dogs that remained seropositive at Day 218, C6 antibody levels declined on average 81% within 84 days of initiating treatment. The results suggest that the APH-4 peptide may be more useful than APH-1 for detecting antibodies earlier in the course of an A. phagocytophilum infection. After doxycycline administration, C6 antibody levels but not APH-1 or APH-4 antibody levels decreased, suggesting a treatment effect on C6 antibody production. (C) 2017 The Author(s). Published by Elsevier Ltd.

87: Theileria buffeli Infections in Grazing Cattle Located in Mountainous Areas of the Republic of Korea Kyoung-Seong Choi*, Joon-Seok Chae, Do-Hyeon Yu, Jinho Park, Bae-Keun Park, Hyeong-Chul Kim Abstract #88: Small Mammals as Hosts of Ehrlichia muris eauclairensis and Other Rickettsial Pathogens in Eau Claire, Wisconsin Bryan N. Ayres*, Audrey E. Osterbind, Jamie L. Perniciaro, Joy A. Hecht, William L. Nicholson Abstract #89: Serological Survey of Canine Tick-borne Infections Using Species-specific Serological Markers Jiayou Lui*, M. E. McCown, C. Fiorello, D. Scorpio, M. Filipovic, J. Saucier, B. Thatcher, R. Chandrashekar Abstract #90: Consistencies in Spatio-Temporal Trends, and Climatic and Other Geospatial Risk Factors for Rickettsial Diseases in the Central Midwestern United States Ram K. Raghavan*, Gary A. Anderson, Doug. G. Goodin, Roman R. Ganta88: Small Mammals as Hosts of Ehrlichia muris eauclairensis and Other Rickettsial Pathogens in Eau Claire, Wisconsin Bryan N. Ayres*, Audrey E. Osterbind, Jamie L. Perniciaro, Joy A. Hecht, William L. Nicholson Abstract #89: Serological Survey of Canine Tick-borne Infections Using Species-specific Serological Markers Jiayou Lui*, M. E. McCown, C. Fiorello, D. Scorpio, M. Filipovic, J. Saucier, B. Thatcher, R. Chandrashekar Abstract #90: Consistencies in Spatio-Temporal Trends, and Climatic and Other Geospatial Risk Factors for Rickettsial Diseases in the Central Midwestern United States Ram K. Raghavan*, Gary A. Anderson, Doug. G. Goodin, Roman R. Ganta Abstract #91: A Distributional Survey of Ticks (Acari: Ixodida) in Georgia, USA William L. Nicholson* Abstract #92: Spotted Fever Group Rickettsiae in Baltic Region Algimantas Paulauskas*, Jana Radzijevskaja, Asta Aleksandraviciene91: A Distributional Survey of Ticks (Acari: Ixodida) in Georgia, USA William L. Nicholson* Abstract #92: Spotted Fever Group Rickettsiae in Baltic Region Algimantas Paulauskas*, Jana Radzijevskaja, Asta Aleksandraviciene Abstract #93: Spotted Fever Group Rickettsia Species Identified among Ticks in Georgia Ekaterine Zhgenti*, Roena Sukhiashvili, Richard J. Obiso, Christina M. Farris, Ju Jiang, Allen L. Richards Abstract #94: Risk Assessment for Vector-borne Diseases at Gateway National Recreation Area, NY: Monitoring Ticks, Preliminary Study, 2014 Ellen Stromdahl*, Garrett Heck, Mary Vince, Waheed Bajwa, Zahir Shah, David Wong93: Spotted Fever Group Rickettsia Species Identified among Ticks in Georgia Ekaterine Zhgenti*, Roena Sukhiashvili, Richard J. Obiso, Christina M. Farris, Ju Jiang, Allen L. Richards Abstract #94: Risk Assessment for Vector-borne Diseases at Gateway National Recreation Area, NY: Monitoring Ticks, Preliminary Study, 2014 Ellen Stromdahl*, Garrett Heck, Mary Vince, Waheed Bajwa, Zahir Shah, David Wong Abstract #95: Evaluating an Ecological Niche Model for Rickettsia montanensis Infected Dermacentor variabilis Based on Ticks Collected from Humans Using Environmentally Captured Ticks Heidi K. St. John*, Penny M. Masuoka, Melissa K. Miller, Melissa L. Adams, Johanna G. Flyer-Adams, Ju Jiang, Patrick J. Rozmajzl, Ellen Y. Stromdahl, Allen L. Richards95: Evaluating an Ecological Niche Model for Rickettsia montanensis Infected Dermacentor variabilis Based on Ticks Collected from Humans Using Environmentally Captured Ticks Heidi K. St. John*, Penny M. Masuoka, Melissa K. Miller, Melissa L. Adams, Johanna G. Flyer-Adams, Ju Jiang, Patrick J. Rozmajzl, Ellen Y. Stromdahl, Allen L. Richards Abstract #96: Survey for Rickettsia Species in Dermacentor variabilis Ticks Collected from National Parks and Monuments across the Eastern United States Sandor E. Karpathy*, Joy A. Hecht, Tammi L. Johnson, Rebecca J. Eisen, Christopher D. Paddock Abstract #97: Flea-borne Rickettsiae in Southeastern Georgia, USA Marina E. Eremeeva*, Danielle Capps, Amanda Jo Williams-Newkirk, Gregory A. Dasch, Lorenza Beati, Lance Durden96: Survey for Rickettsia Species in Dermacentor variabilis Ticks Collected from National Parks and Monuments across the Eastern United States Sandor E. Karpathy*, Joy A. Hecht, Tammi L. Johnson, Rebecca J. Eisen, Christopher D. Paddock Abstract #97: Flea-borne Rickettsiae in Southeastern Georgia, USA Marina E. Eremeeva*, Danielle Capps, Amanda Jo Williams-Newkirk, Gregory A. Dasch, Lorenza Beati, Lance Durden Abstract #98: Prevalence of Q Fever and Rickettsia in Ticks in Northeastern Azerbaijan Rita Ismayilova*, Agarahim Mammadsalahov, Rakif Abdullayev, Esmiralda Seyidova, Sabina Ibrahimova, Elvin Naghiyev98: Prevalence of Q Fever and Rickettsia in Ticks in Northeastern Azerbaijan Rita Ismayilova*, Agarahim Mammadsalahov, Rakif Abdullayev, Esmiralda Seyidova, Sabina Ibrahimova, Elvin Naghiyev Abstract #99: Coxiella burnetii Small RNA 12 (CbsR12) Targets carA Transcripts In vitro Shaun Wachter*, Indu Warrier, Michael F. Minnick99: Coxiella burnetii Small RNA 12 (CbsR12) Targets carA Transcripts In vitro Shaun Wachter*, Indu Warrier, Michael F. Minnick Abstract #100: Alterations in Dermacentor andersoni Transcription in Response to Anaplasma marginale Infection Susan M. Noh*, Forgivemore Magunda, Sebastian Aguilar, Kelly A. Brayton Abstract #101: Characterization of Small, Noncoding RNAs in Rickettsia prowazekii Casey L. C. Schroeder*, Hema P. Narra, Mark Rojas, Abha Sahni, Kamil Khanipov, Jignesh Patel, Yuriy Fofanov, Sanjeev K. Sahni100: Alterations in Dermacentor andersoni Transcription in Response to Anaplasma marginale Infection Susan M. Noh*, Forgivemore Magunda, Sebastian Aguilar, Kelly A. Brayton Abstract #101: Characterization of Small, Noncoding RNAs in Rickettsia prowazekii Casey L. C. Schroeder*, Hema P. Narra, Mark Rojas, Abha Sahni, Kamil Khanipov, Jignesh Patel, Yuriy Fofanov, Sanjeev K. Sahni Abstract #102: Metagenomics of Head Lice Using the Ion Torrent PGM Gregory A. Dasch*, Zachary C. Holmes, T. Brian Shirey, Marina E. Eremeeva, Sarah Zohdy102: Metagenomics of Head Lice Using the Ion Torrent PGM Gregory A. Dasch*, Zachary C. Holmes, T. Brian Shirey, Marina E. Eremeeva, Sarah Zohdy Abstract #103: Decoding the Post-transcriptional Regulatory Networks in Rickettsia conorii Hema P. Narra*, Casey L.C. Schroeder, Abha Sahni, Yuriy Fofanov, Sanjeev K. Sahni Abstract #104: Cytoskeleton Interactions with the Coxiella burnetii Parasitophorous Vacuole Heather Miller*, Charlie Larson, Robert Heinzen103: Decoding the Post-transcriptional Regulatory Networks in Rickettsia conorii Hema P. Narra*, Casey L.C. Schroeder, Abha Sahni, Yuriy Fofanov, Sanjeev K. Sahni Abstract #104: Cytoskeleton Interactions with the Coxiella burnetii Parasitophorous Vacuole Heather Miller*, Charlie Larson, Robert Heinzen Abstract #105: Examination of Tick Vectorial Capacity Factors during Tick-borne Bacterial Infection Kathryn E. Reif*, Jessica K. Ujzco, Deb C. Alprin, Susan M. Noh Abstract #106: Nuclear Trafficking of the Anti-apoptotic Coxiella burnetii Effector Protein AnkG Requires Binding to p32 and Importin-α1 Walter Schäfer*, Rita A. Eckart, Benedikt Schmid, Kerstin Hof, Yves Muller, Bushra Amin, Anja Lührmann105: Examination of Tick Vectorial Capacity Factors during Tick-borne Bacterial Infection Kathryn E. Reif*, Jessica K. Ujzco, Deb C. Alprin, Susan M. Noh Abstract #106: Nuclear Trafficking of the Anti-apoptotic Coxiella burnetii Effector Protein AnkG Requires Binding to p32 and Importin-α1 Walter Schäfer*, Rita A. Eckart, Benedikt Schmid, Kerstin Hof, Yves Muller, Bushra Amin, Anja Lührmann Abstract #107: Effects of Novel Bacteriophage on Abalone Exposed to Candidatus Xenohaliotis californiensis – The Causative Agent of Abalone Withering Syndrome James D. Moore*, Ashley Vater, Barbara A. Byrne Abstract #108: Ehrlichia chaffeensis TRP120 Effector Autoubiquitinates and Contains a C-terminal HECT E3 Ligase Domain Bing Zhu*, Tierra R. Farris, Seema Das, Jere W. McBride Abstract #109: Ehrlichia chaffeensis TRP32 is a Nucleomodulin that Directly Regulates Host Gene Expression Tierra Farris*, Bing Zhu, Jere W. McBride107: Effects of Novel Bacteriophage on Abalone Exposed to Candidatus Xenohaliotis californiensis – The Causative Agent of Abalone Withering Syndrome James D. Moore*, Ashley Vater, Barbara A. Byrne Abstract #108: Ehrlichia chaffeensis TRP120 Effector Autoubiquitinates and Contains a C-terminal HECT E3 Ligase Domain Bing Zhu*, Tierra R. Farris, Seema Das, Jere W. McBride Abstract #109: Ehrlichia chaffeensis TRP32 is a Nucleomodulin that Directly Regulates Host Gene Expression Tierra Farris*, Bing Zhu, Jere W. McBride Abstract #110: Molecular Detection of Rickettsia Species in Ticks and Fleas in Eastern Missouri and Southern Illinois Catherine Santanello*, Redir Barwari110: Molecular Detection of Rickettsia Species in Ticks and Fleas in Eastern Missouri and Southern Illinois Catherine Santanello*, Redir Barwari Abstract #111: Molecular Survey of Arthropod Vectors for Rickettsia in the Eastern Thailand Darunee Utennam*, Kamonwan Siriwatthanakul, Chakrit Hirunpetcharat, Wuttikorn Rodkvamtook, Charnchudhi Chanyasanha, Pimmada Sakpisal, Narupon Kuttasingkee, Yutthapong Sudsawat, Chanakan Suwanbongkot, Jariyanart Gaywee Abstract #112: Rickettsia cf sp. Infection in Thailand Jariyanart Gaywe*, Wuttikon Rodkvamtook, Walairat Pronwiroon, Darunee Utainnam, Piyanate Salyakumthorn, Pimmada Sakpisal, Narupon Kuttasingkee, Kamonwan Siriwatthanakul, Chanakan Suwanbongkot, Allen L. Richards, Suradet Jaruchinda111: Molecular Survey of Arthropod Vectors for Rickettsia in the Eastern Thailand Darunee Utennam*, Kamonwan Siriwatthanakul, Chakrit Hirunpetcharat, Wuttikorn Rodkvamtook, Charnchudhi Chanyasanha, Pimmada Sakpisal, Narupon Kuttasingkee, Yutthapong Sudsawat, Chanakan Suwanbongkot, Jariyanart Gaywee Abstract #112: Rickettsia cf sp. Infection in Thailand Jariyanart Gaywe*, Wuttikon Rodkvamtook, Walairat Pronwiroon, Darunee Utainnam, Piyanate Salyakumthorn, Pimmada Sakpisal, Narupon Kuttasingkee, Kamonwan Siriwatthanakul, Chanakan Suwanbongkot, Allen L. Richards, Suradet Jaruchinda Abstr

To better understand the efficacy of doxycycline and 10% imidacloprid+2.5% moxidectin (Advantage Multi(®); Bayer Animal Health, Shawnee Mission, Kansas) on immature adult Dirofilaria immitis parasites and the results of antigen tests, 12 healthy, randomly selected dogs were experimentally infected with D. immitis and monitored for 407 days. Two dogs in each of three subgroups of four dogs were each infected with six (total of 6 dogs) or 12 (total of 6 dogs) D. immitis infective third-stage larvae (L3) obtained from infected mosquitoes. Doxycycline (10mg/kg per os twice daily×30 days) and 10% imidacloprid+2.5% moxidectin (1ml/kg by topical application every 30 days) treatment was initiated at 105 (Group A) and 149 (Group B) days post infection (PI) in two groups. One subgroup of two dogs given 6 L3 and one subgroup of two dogs given 12 L3 remained as untreated controls (GroupC). Serum obtained regularly throughout the study was evaluated by ELISA (PetChek(®) Heartworm-PF Antigen Test, IDEXX Laboratories, Inc.) for D. immitis adult circulating antigens. Six of the eight dogs in the treated groups had detectable antigenemia starting between 148 and 240 days post infection, but antigen was not detected in any treated dog at the end of the study. In the control subgroups, the dogs that received 6 L3 had no detectable antigen while the two dogs that received 12 L3 had detectable antigen beginning on Day 180 that persisted until the end of the study. None of the infected dogs had evidence of circulating microfilariae. At necropsy, no heartworms were recovered from the treated dogs, but all dogs in the untreated group had viable adult heartworms. These results indicate that early immature adult worms (3.5 and 5 months of age) of D. immitis were susceptible to a combined treatment regimen of doxycycline and 10% imidacloprid+2.5% moxidectin.