ZikaPLAN: Zika Preparedness Latin American Network

The ongoing Zika virus (ZIKV) outbreak in Latin America, the Caribbean, and the Pacific Islands has underlined the need for a coordinated research network across the whole region that can respond rapidly to address the current knowledge gaps in Zika and enhance research preparedness beyond Zika. The European Union under its Horizon 2020 Research and Innovation Programme awarded three research consortia to respond to this need. Here we present the ZikaPLAN (Zika Preparedness Latin American Network) consortium. ZikaPLAN combines the strengths of 25 partners in Latin America, North America, Africa, Asia, and various centers in Europe. We will conduct clinical studies to estimate the risk and further define the full spectrum and risk factors of congenital Zika virus syndrome (including neurodevelopmental milestones in the first 3 years of life), delineate neurological complications associated with ZIKV due to direct neuroinvasion and immune-mediated responses in older children and adults, and strengthen surveillance for birth defects and Guillain-Barré Syndrome. Laboratory-based research to unravel neurotropism and investigate the role of sexual transmission, determinants of severe disease, and viral fitness will underpin the clinical studies. Social messaging and engagement with affected communities, as well as development of wearable repellent technologies against Aedes mosquitoes will enhance the impact. Burden of disease studies, data-driven vector control, and vaccine modeling as well as risk assessments on geographic spread of ZIKV will form the foundation for evidence-informed policies. While addressing the research gaps around ZIKV, we will engage in capacity building in laboratory and clinical research, collaborate with existing and new networks to share knowledge, and work with international organizations to tackle regulatory and other bottlenecks and refine research priorities. In this way, we can leverage the ZIKV response toward building a long-term emerging infectious diseases response capacity in the region to address future challenges.

Evolution of the National Schistosomiasis Control Programmes in The People's Republic of China

Schistosomiasis japonica is caused by the parasitic trematode Schistosoma japonicum. It is endemic in The People's Republic of China and has significant impact on human health and socioeconomic development in certain regions. Over the last six decades, the national control programmes evolved in remarkable ways and brought schistosomiasis japonica largely under control. We describe the history and evolution of schistosomiasis control in The People's Republic of China, with an emphasis on shifts in control strategies that evolved with new insights into the biology of the parasite and its intermediate hosts, and the epidemiology of the disease in the country. We also highlight the achievements in controlling the disease in different socioecological settings, and identify persisting challenges to fully eliminate schistosomiasis japonica from the country. To reach the goal of schistosomiasis elimination, further integration of interventions, multisector collaboration, sensitive and effective surveillance are needed to strengthen.

China-Africa and China-Asia Collaboration on Schistosomiasis Control: A SWOT Analysis

Schistosomiasis, a disease caused by a trematode, parasitic worm, is a worldwide public health problem. In spite of great progress with regard to morbidity control, even elimination of this infection in recent decades, there are still challenges to overcome in sub-Saharan Africa and endemic areas in Southeast Asia. Regarded as one of the most successful countries with respect to schistosomiasis control, The People's Republic of China has accumulated considerable experience and learnt important lessons in various local settings that could benefit schistosomiasis control in other endemic countries. Based on an analysis of conceived strengths, weaknesses, opportunities and threats (SWOT) of potential collaborative activities with regard to schistosomiasis in Africa and Asia, this article addresses the importance of collaborative efforts and explores the priorities that would be expected to facilitate the transfer of Chinese experience to low- and middle-income countries in Africa and Asia.

Prevalence of HIV and Chlamydia trachomatis infection in 15--19-year olds in rural Tanzania

OBJECTIVE

To estimate the prevalence of HIV and Chlamydia trachomatis (CT) infections amongst adolescents in rural Mwanza Region, Tanzania and their association with demographic variables.

DESIGN

Population-based cross-sectional survey.

METHODS

All 15--19-year olds living in households selected by random cluster sampling were invited to participate. After interview, urine was tested for HIV and CT.

RESULTS

9445 15--19-year olds were enrolled. HIV prevalence was 0.6% (95% CI: 0.4--0.8%) in males and 2.4% (95% CI: 2.0--2.8%) in females, and increased steeply with age (trend: P < 0.006 and P < 0.001, respectively). After adjustment for age, risk of HIV infection was significantly associated with female sex (OR=4.3), never having been to primary school in males (OR=2.7), and current symptoms of genital discharge (OR=2.3) or genital ulcer (OR=5.3) in females. The prevalence of CT was 1.0% (95% CI: 0.8--1.4%) in males and 2.4% (95% CI: 2.0-2.9%) in females. After adjustment for age, CT infection was associated with female sex (OR=2.4), reported current symptoms of STD (males OR=2.5, females OR=1.9) and positive leucocyte esterase (LE) test (males OR=3.1, females OR=2.6). Eighty-two percent of males and 79% of females with CT were asymptomatic. There was no association between CT and HIV infection in either sex.

CONCLUSIONS

There is a high prevalence of HIV and CT amongst adolescents, especially young women, in this rural population, highlighting the need for effective interventions to improve adolescent reproductive health. The high rates of asymptomatic infection imply that innovative strategies are needed to reach and treat young people with STD.

Chlamydia pneumoniae major outer membrane protein is a surface-exposed antigen that elicits antibodies primarily directed against conformation-dependent determinants

The major outer membrane protein (MOMP) of Chlamydia trachomatis serovariants is known to be an immunodominant surface antigen. Moreover, it is known that the C. trachomatis MOMP elicits antibodies that recognize both linear and conformational antigenic determinants. In contrast, it has been reported that the MOMP of Chlamydia pneumoniae is not surface exposed and is immunorecessive. We hypothesized that the discrepancies between C. trachomatis and C. pneumoniae MOMP exposure on intact chlamydiae and immunogenic properties might be because the focus of the host's immune response is directed to conformational epitopes of the C. pneumoniae MOMP. We therefore conducted studies aimed at defining the surface exposure of MOMP and the conformational dominance of MOMP antibodies. We present here a description of C. pneumoniae species-specific monoclonal antibody (MAb), GZD1E8, which recognizes a conformational epitope on the surface of C. pneumoniae. This MAb is potent in the neutralization of C. pneumoniae infectivity in vitro. Another previously described C. pneumoniae species-specific monoclonal antibody, RR-402, displayed very similar characteristics. However, the antigenic determinant recognized by RR-402 has yet to be identified. We show by immunoprecipitation of C. pneumoniae with GZD1E8 and RR-402 MAbs and by mass spectrometry analysis of immunoprecipitated proteins that both antibodies GZD1E8 and RR-402 recognize the MOMP of C. pneumoniae and that this protein is localized on the surface of the organism. We also show that human sera from C. pneumoniae-positive donors consistently recognize the MOMP by immunoprecipitation, indicating that the MOMP of C. pneumoniae is an immunogenic protein. These findings have potential implications for both C. pneumoniae vaccine and diagnostic assay development.

The relation between Chlamydia pneumoniae infection and abdominal aortic aneurysm: case-control study

Due to recent interest in the role of Chlamydia pneumoniae as a pathogen of the vascular system, a case-control study was conducted to investigate the association between serological evidence of infection with C. pneumoniae and the occurrence of abdominal aortic aneurysm. Detectable IgG antibody to C. pneumoniae was more common among abdominal aortic aneurysm cases than among control patients (adjusted odds ratio, 5.97; P = .08), as was detectable IgM antibody (10% vs. 0%; P = .02). These findings suggest that infection with C. pneumoniae may play a role in the pathogenesis of abdominal aortic aneurysm; therefore, further research in this area is warranted.

Can an antibiotic (macrolide) prevent Chlamydia pneumoniae-induced atherosclerosis in a rabbit model?

There is increasing data implicating Chlamydia pneumoniae in the pathogenesis of atherosclerosis, and antibiotics may theoretically be useful to prevent secondary vascular complications. Three groups of New Zealand White specific-pathogen-free rabbits, fed cholesterol-free chow, were inoculated via the nasopharynx on three occasions, 2 weeks apart, with C. pneumoniae. Group I (n = 23) rabbits were untreated; group II (n = 24) rabbits were treated with azithromycin at 30 mg/kg of body weight daily for 3 days and then once every 6 days, starting 5 days after first inoculation and continuing until sacrifice (early treatment); and group III (n = 24) rabbits were treated with the same dose of azithromycin but initiated 2 weeks after the last inoculation. All animals were sacrificed at 10 to 11 weeks after initial inoculation and examined for signs of atherosclerosis of the aorta. Eight (34.8%) untreated rabbits developed early signs of atherosclerosis, whereas only one (4.2%) in the early-treatment group had such signs (P = 0.02). However, eight rabbits (33.3%) of the delayed-treatment group had atherosclerotic changes of the aorta and no significant reduction compared to untreated rabbits. Early treatment of C. pneumoniae-infected rabbits with azithromycin was highly effective (87%) in preventing atherosclerotic changes, but delayed treatment was ineffective. It is possible that longer or more aggressive antibiotic treatment may be needed to reverse preformed lesions or that antibiotics may not be of value once lesions have formed.

Chlamydia infection in street youth: Need for more aggressive screening programs

OBJECTIVES

To determine, first, the sexual practices among street youth in the Ottawa-Carleton, Ontario region; second, the percentage of street youth who report previous sexually transmitted disease (STD) screening; and third, the rate of previous infection with Chlamydia trachomatis in this population.

METHODS

This prospective street youth pilot study was cross-sectional in design. Street youth aged 15 to 20 years were recruited through a drop-in centre or shelter in Ottawa, Ontario between August and October 1993. Information on demographics, substance use, current sexual practices and STD screening and infection history were obtained through a structured face to face interview and a 75-item questionnaire. Past C trachomatis infection was determined by microimmunofluorescence assay with purified antigens of C trachomatis (serovars A to K), Chlamydia psittaci (avian strain 6BC) and Chlamydia pneumoniae (TW-183 strain).

RESULTS

Ninety-eight per cent of the youth approached participated. Of the 100 street youth (61 males, mean age 17.8 years; 39 females, mean age 17.1 years), 94% were sexually active, with 21% of males and 26% of females having had four or more different sexual partners in the previous year. Only 27% of males and 8% of females reported consistent condom use with all partners all of the time. Thirty per cent of males and 50% of females reported previous STD testing. Of the 100 street youth, 22 (16 males and six females) had had previous C trachomatis infection by serotesting, but only three of 16 (19%) of these males and three of six (50%) of these females reported previous STD testing. None of the 22 recalled previous diagnosis or treatment for any STD.

CONCLUSIONS

These street youth reported a high prevalence of risky sexual behaviour, and this supports the national STD guidelines for targeted screening in this population. The current screening guidelines for C trachomatis in this population do not reach the majority of street youth.

Vasculitis as the basis of cutaneous lesions in Reiter's disease

The cutaneous lesions of Reiter's disease (RD) and pustular psoriasis (PP) are said to be histologically similar and often indistinguishable. We encountered three cases of RD in which biopsy specimens of lesions clinically compatible with keratoderma blenorrhagicum showed a pustular psoriasiform tissue reaction in conjunction with a subjacent superficial leukocytoclastic vasculitis (LCV). In an attempt to ascertain if these changes were distinctive and unique to cutaneous RD, the incidence of such changes in lesions of PP was examined using light microscopy and immunohistochemistry. The role of chlamydial infection in the pathogenesis of the observed vascular changes also was explored by assessing for the presence or absence of vascular deposition of chlamydial antigen in cutaneous RD compared with that in a control group that included cases of LCV and PP. In addition to conventional light microscopic analysis, immunoperoxidase studies to identify immunoglobulin deposition were performed on formalin-fixed, paraffin-embedded tissue from two of three patients with RD and on skin biopsy specimens from 11 patients with PP. Direct immunofluorescence (DIF) studies with antibodies to immunoglobulin (Ig)G, IgM, IgA, C3, and chlamydial antigens were performed on frozen tissue from one patient with RD, two patients with PP, three patients with LCV, one patient with nonspecific dermatitis, and one patient with Behçet's disease, who had a high antichlamydia antibody titer. All three specimens of RD showed a pustular psoriasiform diathesis in conjunction with a subjacent superficial LCV that was of maximal intensity in the dermal papillae capillaries. Through an immunoperoxidase technique performed on formalin-fixed tissue, the RD cases for which tissue was available for study demonstrated Ig deposition in injured blood vessels; using the same technique one of 11 PP biopsy specimens showed vascular Ig deposition in concert with LCV. This patient's biopsy was from a lesion of drug-induced LCV. None of the other specimens showed either light microscopic or immunohistochemical evidence of vasculitis. In the one specimen of RD studied by DIF, vascular deposition of IgG, IgM, C3, chlamydia heat shock protein 60 (CHSP60), and chlamydia-specific lipopolysaccharide (LPS) was observed. In the two specimens of PP studied, vascular deposition of C3, fibrin, CHSP 60, and chlamydia-specific LPS was not observed. Two specimens of LCV and the one specimen of dermatitis with concomitant nonspecific vascular injury showed vascular Ig and C3 deposition; in contrast, no vascular deposition of CHSP 60 or chlamydia-specific LPS was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Ophthalmia neonatorum in a trachoma endemic area

BACKGROUND AND OBJECTIVES

Chlamydia trachomatis can be directly transmitted by sexual or perinatal contact and indirectly transmitted by flies or fomites. Whether distinct epidemiologic forces among human populations or biologic characteristics of the organism are responsible for the different routes of transmission is uncertain.

STUDY DESIGN

To determine if ophthalmia neonatorum and trachoma are linked epidemiologically, 38 infants with ophthalmia and 277 children with trachoma were studied for evidence of C. trachomatis infection using culture, antigen and DNA detection tests. The study was performed in a trachoma endemic area of central Kenya.

RESULTS

Of infants with ophthalmia neonatorum, 8% to 9% had microbiologic evidence of ocular C. trachomatis infection. Of the children with trachoma, 31% had evidence of chlamydial infection. Ninety-two percent of the 59 identified strains causing trachoma belonged to the classic trachoma serovars (A, B, Ba and C). Neither of the two chlamydial strains recovered from infants with ophthalmia was a trachoma serovar. Mothers rarely (3%) had cervical C. trachomatis infection.

CONCLUSION

This study does not support a major role for perinatally transmitted C. trachomatis infection in trachoma epidemiology.

Association between antibody to the chlamydial heat-shock protein and tubal infertility

To determine the prevalence of antibody to Chlamydia heat-shock protein 60 (C-hsp60) in women with tubal infertility, an ELISA using purified recombinant C-hsp60 was developed. Antibody to C. trachomatis was present in 32 (72.7%) of 44 women with tubal infertility compared with 9 (32.1%) of 28 with other causes of infertility and 55 (28.9%) of 190 pregnant women (P < .001). Among the seropositive women, antibody to C-hsp60 was present in 26 (81.3%) of 32 women with tubal infertility compared with 0 of 9 with other causes of infertility and 9 (16.4%) of 55 pregnant women (P < .001). The C-hsp60 ELISA detected Chlamydia-associated tubal infertility in infertile women with a sensitivity of 81.3% and a specificity of 97.5%. There is a strong association between antibody response to the C-hsp60 and the development of Chlamydia-associated tubal infertility. Thus, a C-hsp60 ELISA may be useful as a predictor for poor fertility outcome.

Chlamydia trachomatis-associated ectopic pregnancy: serologic and histologic correlates

Fifty-five women with ectopic pregnancy and 24 undergoing tubal ligation with a segmental resection of the fallopian tube were evaluated for histopathology of the fallopian tube, Chlamydia trachomatis serum antibodies, antibodies to a chlamydial sarkosyl-soluble 57-kDa protein, and for isolation of C. trachomatis. Plasma cell infiltration in the fallopian tube submucosa was identified in 31 (65%) of 48 women with ectopic pregnancies and in 8 (33%) of 24 undergoing tubal ligation (P = .01; odds ratio [OR], 3.6; 95% confidence interval [CI], 1.3-10.3). Plasma cell infiltration was correlated with C. trachomatis seropositivity among women with ectopic pregnancy (P = .005; OR, 7.2; 95% CI, 1.7-31) and among women undergoing tubal ligation (P = .008). Of 21 C. trachomatis-seropositive women with ectopic pregnancies, 19 had antibodies to the 57-kDa antigen compared with 1 of 4 seropositive women having tubal ligation (P = .008). Immune responses to the 57-kDa antigen may be involved in the immunopathogenesis of C. trachomatis-associated ectopic pregnancy.

Immunologic characterization of a cloned fragment containing the species-specific epitope from the major outer membrane protein of Chlamydia trachomatis

A 183-bp fragment encoding variable domain IV (VD IV) of Chlamydia trachomatis serovar B major outer membrane protein (MOMP) (amino acids 273 to 333) and containing the species-specific epitope was cloned and expressed in Escherichia coli as a fusion protein with Schistosoma japonicum glutathione S-transferase (GST-VD IV). The fusion protein was affinity purified under nondenaturing conditions and used to immunize rabbits. Antisera were characterized by microimmunofluorescence, immunoblot, dot blot, peptide enzyme-linked immunosorbent, and in vitro neutralization assays. Antisera recognized MOMP from all 12 tested serovars of C. trachomatis but not from Chlamydia psittaci. In a dot blot assay, antisera bound to elementary bodies of serovars B, D, E, L2, and K in a strong fashion and to elementary bodies of serovars F, G, A, and H in a weak fashion but not to elementary bodies of serovars C, J, and I. High-resolution peptide mapping with synthetic overlapping serovar B MOMP peptides in a solid-phase enzyme-linked immunosorbent assay showed that immunization with GST-VD IV produced a serologic response that closely mimicked the response produced with purified serovar B elementary bodies. Antipeptide antibodies with strong binding to species- and subspecies-specific epitopes were elicited. Antisera were able to neutralize only those C. trachomatis serovars that bound antibodies in the dot blot assay. These results suggest that antigenic fragments from VD IV containing the species-specific epitope may be useful in the construction of a chlamydial vaccine for some but not all C. trachomatis serovars.

The prevalence of Chlamydia trachomatis infection among mothers of children with trachoma

The authors studied the epidemiology of Chlamydia trachomatis infection in a trachoma-endemic area of central Kenya. Children with abnormal ocular discharge were evaluated for clinical evidence of trachoma and were cultured for C. trachomatis. Isolated strains of C. trachomatis were immunotyped with monoclonal antibodies. Overall, 221 children from 207 families were evaluated. Clinically, 91 children (41%) had trachomatous follicular inflammation, and 130 (59%) had papillary hypertrophy without visible follicle and were labeled as having mucopurulent conjunctivitis. C. trachomatis was isolated from 31 of 91 children with trachoma (34%) and 17 of 130 children with conjunctivitis (13%) (p less than 0.001). Twenty-two C. trachomatis strains were immunotyped: 17 were from children with trachoma (nine type A, one A/L2, five B, one Ba, and one E) and five were from children with conjunctivitis (two A, one Ba, one D, and one F). A total of 168 mothers were evaluated for cervical C. trachomatis infection, and seven (4%) were culture-positive. Two strains were immunotyped as serovar E. The authors conclude that C. trachomatis ocular infections are due to heterogeneous serovars in this area, that most cases of trachoma are due to C. trachomatis infection with the classic trachoma serovars (A, B, or Ba), and that cervical C. trachomatis infection is uncommon among mothers of children with trachoma.

The 75-kilodalton protein of Chlamydia trachomatis: a member of the heat shock protein 70 family?

The gene encoding a 75-kilodalton (kDa) protein of Chlamydia trachomatis was cloned, expressed, and sequenced. Genomic libraries from C. trachomatis serovar D DNA were constructed in vectors pUC18 and lambda gt11 and were screened with a panel of monoclonal antibodies against C. trachomatis antigens. The only recombinants identified were those that reacted with antibody UM-13, which has specificity for a genus-specific epitope on the 75-kDa protein. The gene was localized to a 2.9-kilobase DNA fragment and sequenced. The gene consists of a long open reading frame of 1,956 nucleotides, which translates into 652 amino acids totalling 70,558 daltons in mass. Putative promoter elements and a ribosome binding site were identified within 5'-flanking sequences, and a typical rho-independent terminator was identified within 3'-flanking sequences. Screening of the GenBank nucleic acid sequence data bank revealed extensive similarity between the chlamydial 75-kDa gene and the heat shock protein 70 (hsp70) family or proteins. In particular, 71 and 69% amino acid sequence similarities were identified with hsp70 of Escherichia coli and Bacillus megaterium, respectively. Polyclonal antibodies were produced to the recombinant antigen in rabbits and detected epitopes on elementary bodies in enzyme-linked immunosorbent and indirect microimmunofluorescence assays. Antibodies reacted with an antigen of identical molecular mass in L2 and C serovars in an immunoblot assay and neutralized these serovars in cell culture. The 75-kDa protein appears to be a chlamydial homolog of hsp70, is immunoaccessible on native elementary bodies, and is a target for neutralization.

Postabortal Chlamydia trachomatis salpingitis: correlating risk with antigen-specific serological responses and with neutralization

Serum antibodies to Chlamydia trachomatis were studied by microimmunofluorescence (micro-IF) testing and by immunoblotting among 52 women with C. trachomatis cervical infection. All women underwent therapeutic abortion, and 10 (19.2%) subsequently developed laparoscopically confirmed salpingitis. Women who developed salpingitis had lower geometric mean titers of micro-IF antibody before abortion (14.9 x/divided by 2.3) than did women who did not develop salpingitis (41.6 x/divided by 4.9, P less than .01). Women who developed salpingitis significantly less often had serum IgA antibodies to a 60-kilodalton (kDa) chlamydial antigen (P = .02) and IgG antibodies to antigens of 75-kDa (P = .008), 60-kDa (P = .03), and 57-kDa (P = .0003). Serum antibodies to 100-kDa, 32-kDa, and 29-kDa antigens occurred only in women who did not develop salpingitis. Differences in antibody prevalence to specific chlamydial antigens were not due to differences in serum antibody titers between the two groups. No correlation between neutralizing sera and the risk of postabortal salpingitis was detected.

In vitro neutralization of Chlamydia trachomatis with monoclonal antibody to an epitope on the major outer membrane protein

A murine monoclonal antibody, which binds to an epitope on the major outer membrane protein of Chlamydia trachomatis and with species specificity in the micro-immunofluorescent assay, effectively neutralized in vitro two antigenically distinct serovars of C. trachomatis. Optimal concentrations of both organism and antibody were required to produce maximal neutralization of the organism. Neutralization was less effective and more variable at lower dilutions of antibody than at higher dilutions, suggesting a prozone phenomenon. A radiolabeled attachment assay demonstrated that attachment of elementary bodies was unaffected by earlier treatment with antibody and that neutralization occurred at a step after attachment. The epitope to which this antibody is directed, on the major outer membrane protein of C. trachomatis, may have an important role in determining infectivity of the organism.