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Purpose: Psittacosis is a bacterial zoonosis caused by Chlamydia (Chlamydophila) psittaci that infects birds. Although potentially fatal, infections can be reduced by controlling the source of infection. We therefore described the epidemiology of psittacosis, focusing on the infection source., Methods: We descriptively analyzed psittacosis cases reported through national surveillance in Japan from 2007 to 2016. We also analyzed Chlamydia psittaci prevalence among captive psittaciformes during the same period., Results: One hundred eleven cases were reported, and the annual number and notification rate of psittacosis declined. While 58% were male and the median age was 61 years, the median age differed by gender (males: 63 years, females: 53 years), with more female cases in those aged <50 years. In addition, the most common infection source differed by gender (men: columbiformes; women: psittaciformes). The decline in notifications was associated with a decline in psittaciformes-associated cases, with a concomitant decline in female cases. The prevalence of C. psittaci among captive psittaciformes also decreased over the period., Conclusions: We found important differences in the epidemiology of psittacosis by gender, and the recent decrease in notifications correlated with decreasing C. psittaci prevalence in birds. Risk communications for psittacosis should consider the current epidemiology regarding gender, age, and infection source., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A serological survey was carried out in the northern prefectures of Hokkaido, Iwate and Aomori in Japan, for the presence of antibodies against Toxoplasma gondii, Chlamydiapsittaci var. ovis, Mycobacterium paratuberculosis, Coxiella burnetii, Brucella spp., Leptospirosis and Orf virus (ORFV). Out of 267 samples tested, highest overall prevalence (28.78%) was found for T. gondii. The 12.59% of tested sheep were positive for C. psittaci var. ovis. A total of 8.67% were found to be seropositive for C. burnetii. Levels of these infections were found in all three prefectures. Seroconversion to ORFV was detected in Hokkaido and Iwate Prefectures (2.57%). Animals were positive only for L. ballum (1.50%), in Hokkaido and Aomori Prefectures. No animals tested positive for Brucella spp. and M. paratuberculosis.

Psittacosis outbreak due to Chlamydophila psittaci occurred among staff members at an avian exhibition of nearly 1,000 birds in Kobe, Japan, in December 2005. Staff members not trained about zoonosis or psittacosis used little protective attire such as masks and gloves when caring for their discharges. Two of 67 staff members contracted psittacosis pneumonia. Additional two suffered from pneumonia and 19 reported symptoms such as fever and cough, although none were diagnosed with psittacosis. The roughly 970 birds were kept without quarantine and identified by leg bands. Doxycycline administrated in drinking water and food failed to eradicate chlamydia, so all birds were captured, identified by leg band, and tested for chlamydia by PCR. Six were found to carry large amounts of chlamydia. Major outer membrane protein (MOMP) DNA sequence of chlamydia in a patient's bronchoalveolar lavage fluid (BALF) was identical to that derived from a channel-billed toucan kept in a closed aviary, and staff members may have been infected by inhaling excrement while working in the aviary. The MOMP DNA sequence was useful in comparing strains. We review the difficulty of diagnosing psittacosis and the knowledge and infection control measures required against it.

An outbreak of psittacosis related to a bird park occurred in Matsue City, Shimane Prefecture, Japan, during winter 2001. Seventeen cases of psittacosis (12 visitors, three staff, and two student interns) were confirmed. A cohort study was conducted among the park staff and students to determine the risk factors for the development of acute serologically confirmed psittacosis (SCP) infection. Being 'bird staff' had an increased risk of SCP infection (RR 3.96, 95% CI 1.48-10.58). Entering the staff building, where ill birds were maintained without proper isolation, was also associated with an increased risk of SCP infection (RR 3.61, 95% CI 1.03-12.6). Isolation of ill birds and quarantine measures were found to be insufficient. Dehumidifiers and a high-pressure water spray under a closed ventilation environment may have raised the concentration of Chlamydophila psittaci in the hothouses. Bird park staff and visitors should be educated about psittacosis.

The prevalence of chlamydia antibodies in Japan was investigated in 215 cat sera, consisting of 88 sera of stray cats and 127 sera of pet cats, and 2,184 human sera, taken from 2,003 general persons and 181 small animal clinic veterinarians, by microimmunofluorescence (MIF) testing with Chlamydia psittaci Fe/Pn1 of feline origin and Prk/6BC of avian origin as antigens. The prevalence rates of anti-Fe/Pn1 antibodies were 45.5% in stray cats, 17.3% in pet cats, 1.7% in general persons and 8.8% in small animal clinic veterinarians. The prevalence rates of anti-Prk/6BC antibodies were 51.1% in stray cats, 15.0% in pet cats, 3.1% in general persons and 5.0% in small animal clinic veterinarians. These results suggested that feline chlamydia infection is widely spread in cats especially in stray cats in Japan, and suggested that feline chlamydiosis could be transmitted to people who are in close contact with infected cats.

The prevalence of anti-chlamydia antibodies was examined in 232 cat sera collected in 1985 and from 1993 to 1995 from laboratories and veterinary hospitals located in 11 prefectures of Japan. The antibodies were determined by an indirect microimmunofluorescence test using six strains of feline Chlamydia: one strain each of avian- and guinea pig-derived C. psittaci and one strain each of C.pecorum, C.pneumoniae and C.trachomatis. Positive rates of IgG antibodies to chlamydiae were 34.4% in 1985 and 16.5-21.4% from 1993 to 1995. Positive rates of IgM antibodies to chlamydiae were 8.2% in 1985 and 6.6-14.3% from 1993 to 1995. Variations in antibody reactivity to the different feline strains were observed. The results suggest the wide prevalence of chlamydial infection in cats in Japan, and antigenic diversity in the feline strains of C.psittaci.

To investigate the overall prevalence of chlamydial infections in light (i.e. non-draught) horses in Japan, 599 sera obtained from 12 localities in 1991 were tested for complement fixation antibodies. The mean antibody positive rates of the all sera were 15.2% (91/599) and the regional positive rates were higher in Honshu (19.1%, 48/251) and Kyushu (20.0%, 20/100) than in Hokkaido (9.3%, 23/248). In Honshu, the highest rate (56.0%, 28/50) was observed in Utsunomiya. Analysis of the positive rate in different age groups showed that the 2-5 years age-group had the highest prevalence of chlamydial infections. This indicates that chlamydial infection is prevalent in light horses in Japan.

An outbreak of abortion in cows occurring in Niigata Prefecture was shown to be caused by Chlamydia psittaci. Elementary bodies characteristic of Chlamydia were found in the liver of aborted fetuses and C. psittaci antigen was demonstrated by indirect immunofluorescence. Chlamydia was isolated from the liver of aborted fetuses by the yolk sac inoculation of developing chick embryos and by the intraperitoneal inoculation of guinea pigs. Abortion occurred mostly in middle or late pregnancy. Aborted fetuses showed subcutaneous edema and gelatinous infiltration, enlarged liver and spleen, and dark red pleural and ascitic fluid. Focal necrosis was shown in the liver, spleen and lymph nodes. Serological findings and isolation of Chlamydia from fecal specimens indicated a wide dissemination of C. psittaci among cows in the area.