Patricia P. Wilkins’s research while affiliated with Centers for Disease Control and Prevention and other places

Babesia duncani is the causative agent of babesiosis in the western United States. The indirect fluorescent antibody (IFA) assay is the diagnostic test of choice for detection of B. duncani specific antibodies. However, this test requires parasitized red blood cells harvested from infected hamsters and test results are often difficult to interpret. To simplify serological testing for B. duncani , a proteomics approach was employed to identify candidate immunodiagnostic antigens. Several proteins were identified by electrospray ionization (ESI) mass spectrometric analysis and four recombinant protein constructs were expressed and used in a multiplex bead assay (MBA) to detect B. duncani -specific antibodies. Two antigens, AAY83295.1 and AAY83296.1, performed well with high sensitivities and specificities. AAY83295.1 had a higher sensitivity (100%) but lower specificity (89%) in comparison to AAY83296.1, which had a sensitivity of 90% and a specificity of 96%. Combining these two antigens did not improve the performance of the assay. This MBA could be useful for diagnosis, serosurveillance, and blood donor screening for B. duncani infection.

Se evaluó el uso de partículas magnéticas acopladas a proteína L para la concentración y purificación de anticuerpos monoclonales inmunoglobulina M (mIgM) contra Taenia solium. Se evaluaron tres métodos de concentración y diferentes tiempos de elución y se optimizó la proporción de partículas a la proporción de mIgM. Demostramos que: 1) con el uso partículas magnéticas no se requiere de una concentración previa de mIgM, lo que disminuye la manipulación de los anticuerpos y mejora la recuperación, 2) se puede omitir el uso de un tampón de unión, ya que el pH de la mayoría de los sobrenadantes de cultivo celular son neutros, y 3) se necesitan tiempos de elución más largos (~45 minutos) para aumentar la recuperación a un nivel mayor a 80%. El estudio demuestra que el uso de partículas magnéticas acopladas a proteína L es una herramienta simple y eficiente para la concentración y purificación de mIgM.

In Africa, urbanization is happening faster than ever before which results in new implications for transmission of infectious diseases. For the zoonotic parasite Taenia solium, a major cause of acquired epilepsy in endemic countries, the prevalence in urban settings is unknown. The present study investigated epidemiological, neurological, and radiological characteristics of T. solium cysticercosis and taeniasis (TSCT) in people with epilepsy (PWE) living in Dar es Salaam, Tanzania, one of the fastest growing cities worldwide. A total of 302 PWE were recruited from six health centers in the Kinondoni district of Dar es Salaam. Serological testing for T. solium cysticercosis-antigen (Ag) and -antibodies (Abs) and for T. solium taeniasis-Abs was performed in all PWE. In addition, clinical and radiological examinations that included cranial computed tomography (CT) were performed. With questionnaires, demographic data from study populations were collected, and factors associated with TSCT were assessed. Follow-up examinations were conducted in PWE with TSCT. T. solium cysticercosis-Ag was detected in three (0.99%; 95% CI: 0–2.11%), -Abs in eight (2.65%; 95% CI: 0.84–4.46%), and taeniasis-Abs in five (1.66%; 95% CI: 0.22–3.09%) of 302 PWE. Six PWE (1.99%; 95% CI: 0.41–3.56%) were diagnosed with neurocysticercosis (NCC). This study demonstrates the presence of TSCT in Dar es Salaam, however, NCC was only associated with a few cases of epilepsy. The small fraction of PWE with cysticercosis- and taeniasis-Abs may suggest that active transmission of T. solium plays only a minor role in Dar es Salaam. A sufficiently powered risk analysis was hampered by the small number of PWE with TSCT; therefore, further studies are required to determine the exact routes of infection and risk behavior of affected individuals.

Background: Due to their close relationship with the environment, Alaskans are at risk for zoonotic pathogen infection. One way to assess a population's disease burden is to determine the seroprevalence of pathogens of interest. The objective of this study was to determine the seroprevalence of 11 zoonotic pathogens in people living in Alaska. Methods: In a 2007 avian influenza exposure study, we recruited persons with varying wild bird exposures. Using sera from this study, we tested for antibodies to Cryptosporidium spp., Echinococcus spp., Giardia intestinalis, Toxoplasma gondii, Trichinella spp., Brucella spp., Coxiella burnetii, Francisella tularensis, California serogroup bunyaviruses, and hepatitis E virus (HEV). Results: Eight hundred eighty-seven persons had sera tested, including 454 subsistence bird hunters and family members, 160 sport bird hunters, 77 avian wildlife biologists, and 196 persons with no wild bird exposure. A subset (n = 481) of sera was tested for California serogroup bunyaviruses. We detected antibodies to 10/11 pathogens. Seropositivity to Cryptosporidium spp. (29%), California serotype bunyaviruses (27%), and G. intestinalis (19%) was the most common; 63% (301/481) of sera had antibodies to at least one pathogen. Using a multivariable logistic regression model, Cryptosporidium spp. seropositivity was higher in females (35.7% vs. 25.0%; p = 0.01) and G. intestinalis seropositivity was higher in males (21.8% vs. 15.5%; p = 0.02). Alaska Native persons were more likely than non-Native persons to be seropositive to C. burnetii (11.7% vs. 3.8%; p = 0.005) and less likely to be seropositive to HEV (0.4% vs. 4.1%; p = 0.01). Seropositivity to Cryptosporidium spp., C. burnetii, HEV, and Echinococcus granulosus was associated with increasing age (p ≤ 0.01 for all) as was seropositivity to ≥1 pathogen (p < 0.0001). Conclusion: Seropositivity to zoonotic pathogens is common among Alaskans with the highest to Cryptosporidium spp., California serogroup bunyaviruses, and G. intestinalis. This study provides a baseline for use in assessing seroprevalence changes over time.

Objective: To evaluate the diagnostic performance of two commercially available ELISA kits, Novalisa(®) and Ridascreen(®) , for the detection of antibodies to Taenia solium, compared to serological diagnosis of neurocysticercosis (NCC) by LLGP-EITB (electro immunotransfer blot assay using lentil-lectin purified glycoprotein antigens). Methods: Archive serum samples from patients with viable NCC (n=45) or resolved, calcified NCC (n=45), as well as sera from patients with other cestode parasites (hymenolepiasis, n=45, and cystic hydatid disease, n=45), were evaluated for cysticercosis antibody detection using two ELISA kits, Novalisa(®) and Ridascreen(®) . All NCC samples had previously tested positive and all samples from heterologous infections were negative on LLGP-EITB for cysticercosis. Positive rates were calculated by kit and sample group and compared between the two kits. Results: Compared to LLGP-EITB, the sensitivity of both ELISA assays to detect specific antibodies in patients with viable NCC was low (44.4% and 22.2%), and for calcified NCC it was only 6.7% and 4.5%. Sera from patients with cystic hydatid disease were highly cross-reactive in both ELISA assays (38/45, 84.4%; and 25/45, 55.6%). Sera from patients with hymenolepiasis cross-reacted in five cases in one of the assays (11.1%), and in only one sample with the second (2.2%). Conclusions: The performance of Novalisa(®) and Ridascreen(®) was poor. Antibody ELISA detection cannot not be recommended for the diagnosis of neurocysticercosis. This article is protected by copyright. All rights reserved.

Background Extensive testing for infectious diseases is typically performed on refugees, but these tests are not provided to immigrants who often share similar risk factors. In 2015, approximately 42.1 million persons living in the United States were immigrants, many of whom migrated from countries where parasitic infections are highly prevalent. Methods We recruited 133 asymptomatic recent immigrants into a cross-sectional study to assess the prevalence of parasitic infections in this population. Participants were asked a symptom questionnaire and provided stool samples for Ova & Parasite (O&P) exam and blood samples for eosinophil count and Immunoglobulin E (IgE) level; samples were also tested for parasite-specific serologies. Results Enrolled subjects had a mean age of 32.1 years (SD 17.3) and 73 of the 133 subjects were female (54.9%). Subjects had immigrated primarily from Mexico (29/133, 21.8%), India (25/133, 18.8%), other Asian countries (33/133, 24.8%), and Central and South America (26/133, 19.5%). Twenty of 133 subjects (15%) tested positive for a parasitic infection. Subjects underwent serologic testing based on their reported country of origin. The most commonly identified infections were: Blastocystis hominis (9/119 samples tested, 7.6%), followed by Toxocara (6/73, 8.2%), schistosomiasis (5/73, 6.8%), strongyloidiasis (3/73, 4.1%), and Chagas disease (1/73, 1.4%). Among 133 subjects, 29 (21.8%) were found to have an elevated IgE level (GM value of those with elevated IgE: 435.3 IU/ml), while 12/133 (9%) had an elevated absolute eosinophil count (AEC). There was no difference in gender (P = 0.63) or recency of immigration (P = 0.23) between those with and without parasitic infections. IgE was significantly higher in those with a parasitic infection (GM 136.7 IU/ml) compared with those without (GM 65.53 IU/ml, P = 0.03), but mean AEC was not significantly different between the groups (P = 0.69). None of the reported symptoms, including itching, hives, rash, abdominal pain, diarrhea, or wheezing were increased in those with a parasitic infection (all P-values >0.05). Conclusion Based on our preliminary data, parasitic infections likely represent a large and as-yet-unidentified burden of disease in the immigrant population. Immigrants may therefore benefit from health screenings as are provided to refugees. Disclosures All authors: No reported disclosures.

Questionnaire used in a study of the seroprevalence of Baylisascaris procyonis infection in humans, Santa Barbara County, California, USA, 2014–2016.

De-identified data collected in a study of the seroprevalence of Baylisascaris procyonis infection in humans, Santa Barbara County, California, USA, 2014–2016.

Despite the global distribution and public health consequences of Taenia tapeworms, the life cycles of taeniids infecting wildlife hosts remain largely undescribed. The larval stage of Taenia serialis commonly parasitizes rodents and lagomorphs, but has been reported in a wide range of hosts that includes geladas (Theropithecus gelada), primates endemic to Ethiopia. Geladas exhibit protuberant larval cysts indicative of advanced T. serialis infection that are associated with high mortality. However, non-protuberant larvae can develop in deep tissue or the abdominal cavity, leading to underestimates of prevalence based solely on observable cysts. We adapted a non-invasive monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) to detect circulating Taenia spp. antigen in dried gelada urine. Analysis revealed that this assay was highly accurate in detecting Taenia antigen, with 98.4% specificity, 98.5% sensitivity, and an area under the curve of 0.99. We used this assay to investigate the prevalence of T. serialis infection in a wild gelada population, finding that infection is substantially more widespread than the occurrence of visible T. serialis cysts (16.4% tested positive at least once, while only 6% of the same population exhibited cysts). We examined whether age or sex predicted T. serialis infection as indicated by external cysts and antigen presence. Contrary to the female-bias observed in many Taenia-host systems, we found no significant sex bias in either cyst presence or antigen presence. Age, on the other hand, predicted cyst presence (older individuals were more likely to show cysts) but not antigen presence. We interpret this finding to indicate that T. serialis may infect individuals early in life but only result in visible disease later in life. This is the first application of an antigen ELISA to the study of larval Taenia infection in wildlife, opening the doors to the identification and description of infection dynamics in reservoir populations.

Full adapted protocol for the detection of Taenia antigen in dried urine. (DOCX)