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Filth fly parasites reared by commercial insectaries were released on two dairies (MO, DG) in southern California to determine their effect on populations of house flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.). Spalangia endius Walker, Muscidifurax raptorellus Kogan and Legner, and Muscidifurax zaraptor Kogan and Legner were released on the MO dairy from 1985 to 1987 in varying quantities. Parasitism by Muscidifurax zaraptor on the MO dairy was significantly higher (P less than 0.05) from the field-collected stable fly (4.4%) and house fly (12.5%) pupae, compared with a control dairy (0.1%, stable fly; 1.3%, house fly). Muscidifurax zaraptor, released from April through October during 1987 on the DG dairy (350,000 per month), was not recovered in a significantly higher proportion from either fly species relative to the corresponding control dairy. No specimens of Muscidifurax raptorellus were recovered from the MO dairy. Parasite treatments had no apparent effect on adult populations of either fly species or on overall parasitism rate of field-collected stable fly (16.8%, MO; 17.2%, DG) and house fly (23.3%, MO; 20.9%, DG) pupae. Spalangia spp. were the predominant parasites recovered from field-collected stable fly and house fly pupae on all four dairies. Sentinel house fly pupae placed in fly-breeding sites on both release dairies were parasitized at a significantly higher rate, as compared with sentinel pupae on control dairies. The generic composition of parasites emerging from sentinel house fly pupae was 20.6% Spalangia spp. and 73.2% Muscidifurax spp., whereas in field-collected house fly pupae, Spalangia spp. and Muscidifurax spp. constituted 74.3 and 19.6% of the parasites, respectively.

Abstract. A nested polymerase chain reaction specific for Ehrlichia chaffeensis was used to attempt to amplify DNA from extracts of 100 individual ticks collected from 13 counties in central Missouri. Seventeen of 59 Amblyomma americanum and six of 41 Dermacentor variabilis ticks exhibited the characteristic 389-basepair product. This supports the hypothesis that these tick species may be vectors of human monocytic ehrlichiosis.Human monocytic ehrlichiosis is a nonspecific febrile illness first described in 1987. 1 Based on epidemiologic and polymerase chain reaction (PCR) studies, the etiologic agent, Ehrlichia chaffeensis, is believed to be transmitted predominantly by the Lone Star tick, Amblyomma americanum. 2,3 Missouri is one of the leading states for reported cases of human monocytic ehrlichiosis.The PCR has been used to demonstrate the presence of the 16S rRNA gene sequence of E. chaffeensis in extracts of pooled ticks and in individual ticks. 3,4 The former method used DNA extracted from a pool of ticks to potentially increase target DNA sequences, while the latter was felt to lack sensitivity.A nested PCR greatly enhances sensitivity of detection of target nucleic acid sequences. 5 This method has been used to increase the sensitivity for detection of E. chaffeensis in the blood of white-tailed deer. 6 We now report the results of applying an E. chaffeensis-specific nested PCR technique to 100 individual ticks of the species A. americanum and Dermacentor variabilis collected from 13 counties in Missouri. MATERIALS AND METHODSTicks were collected during the spring and summer of 1995 from 13 different counties in Missouri (Figure 1). Sources of the ticks included vegetation, domestic animals, and humans. The species, sex, and stage of development of each tick were identified by an entomologist; the sex of nymphal ticks could not be determined by visual inspection.DNA was extracted from ticks by a modification of a method previously described. 4 Briefly, individual ticks were placed in 200 l of water, crushed, and boiled for 10 min. This material was diluted 1:2 in 10 mM Tris, pH 8.0, 10 mM NaCl and lysed in the presence of 1.0% sodium dodecyl sulfate and 100 ng of proteinase K/ml for 2 hr at 50ЊC. The lysed suspension was extracted twice with an equal volume of phenol-chloroform. A 1:10 dilution of 3 M sodium acetate, pH 5.5, and a 1:1,000 dilution of 20 mg/ml of glycogen (Boehringer Mannheim, Indianapolis, IN) were added to the extracted aqueous phase. The DNA was precipitated with cold ethanol, washed once with 70% ethanol, dried, and resuspended in 40 l of water.The DNA templates from individual ticks were examined by PCR by a modification of a method previously described. 6 For the initial amplification, 10 l of each template sample was amplified in a 60-l reaction mixture containing the primers ECB (5Ј-CGTATTACCGCGGCTGCTGGCA-3Ј) and EG1 (5Ј-CTCAGAACGAACGCTGGCGG-3Ј) and GeneAmp reagents (Perkin-Elmer Cetus, Norwalk, CT) at concentrations described in the GeneAmp protocol. ECB is part of the primer se...

Aims: 16S rDNA sequences of Borrelia burgdorferi sensu lato were aligned with the 16S rDNA sequences of Borrelia hermsii, Borrelia turicatae, and Borrelia lonestari in order to identify primers that might be used to more specifically identify agents of human Lyme disease in ticks in human skin samples. Methods and Results: Standard polymerase chain reaction (PCR), using an oligonucleotide sequence, designated TEC1, was shown, in combination with a previously developed primer (LD2) to amplify strains of B. burgdorferi sensu stricto, Borrelia afzelii, and Borrelia garinii, but not the non-Lyme causing B. hermsii or B. turicatae. This primer pair, designated Bbsl, was successfully used to amplify B. burgdorferi sensu lato from skin biopsies of patients with Lyme disease symptoms as well as from Ixodes scapularis, Amblyomma americanum and Dermacentor variabilis ticks. Conclusions: The primer set Bbsl allows for the rapid detection and differentiation of B. burgdorferi sensu lato from non-Lyme disease-causing Borrelia species in ticks and human tissues. Significance and Impact of the Study: The PCR primer set, Bbsl, will greatly facilitate detection of the causative agents of Lyme disease in infected ticks and human skin samples assisting in epidemiological studies, and potentially allowing for a more rapid diagnosis of the disease in patients.