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Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), remains the world’s leading preventable infectious cause of blindness. Recent attempts to develop effective vaccines rely on modified chlamydial antigen delivery platforms. As the mechanisms engaged in the pathology of the disease are not fully understood, designing a subunit vaccine specific to chlamydial antigens could improve safety for human use. We propose the delivery of chlamydia-specific antigens to the ocular mucosa using particulate carriers, bacterial ghosts (BGs). We therefore characterized humoral and cellular immune responses after conjunctival and subcutaneous immunization with a N-terminal portion (amino acid 1–893) of the chlamydial polymorphic membrane protein C (PmpC) of Ct serovar B, expressed in probiotic Escherichia coli Nissle 1917 bacterial ghosts (EcN BGs) in BALB/c mice. Three immunizations were performed at two-week intervals, and the immune responses were evaluated two weeks after the final immunization in mice. In a guinea pig model of ocular infection animals were immunized in the same manner as the mice, and protection against challenge was assessed two weeks after the last immunization. N-PmpC was successfully expressed within BGs and delivery to the ocular mucosa was well tolerated without signs of inflammation. N-PmpC-specific mucosal IgA levels in tears yielded significantly increased levels in the group immunized via the conjunctiva compared with the subcutaneously immunized mice. Immunization with N-PmpC EcN BGs via both immunization routes prompted the establishment of an N-PmpC-specific IFNγ immune response. Immunization via the conjunctiva resulted in a decrease in intensity of the transitional inflammatory reaction in conjunctiva of challenged guinea pigs compared with subcutaneously and non-immunized animals. The delivery of the chlamydial subunit vaccine to the ocular mucosa using a particulate carrier, such as BGs, induced both humoral and cellular immune responses. Further investigations are needed to improve the immunization scheme and dosage.

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Between December 2010 and August 2011 an outbreak of measles occurred in Serbia with 363 reported cases. Sera and/or nose/throat swabs were collected from 193 patients and tested for measles-specific IgM antibodies by ELISA and viral RNA by RT-PCR, respectively. Epidemiological data were obtained from the surveillance database of the Institute of Public Health of Serbia. Of the 363 cases involved in the outbreak, 113 were laboratory confirmed. More than one third of the patients were hospitalized (n = 130, 35·8%) and for 15 (4·1% of the reported outbreak cases) the infection was complicated by pneumonia. Mostly pre-school children aged ⩽4 years (37·8%) and adults aged ⩾30 years (27·3%) were affected. The majority of patients belonged to the Roma population with a preponderance of female cases (57·0%). Nearly 94% of the patients were either unvaccinated or of unknown vaccination status. The main outbreak virus was the D4-Hamburg strain. The outbreak in Serbia occurred after several years of very low measles incidence despite a high routine immunization coverage in the general population, suggesting that special efforts to identify and vaccinate susceptible population groups are required even in countries with apparently good disease control.