Eyedrop Inoculation Causes Sublethal Leptospirosis in Mice.

Leptospirosis is potentially a fatal zoonosis acquired by contact of skin and mucosal surfaces with soil and water contaminated with infected urine. We analyzed the outcome of infection of C3H/HeJ mice with Leptospira interrogans serovar Copenhageni using an enzootic mode of transmission, the conjunctival route. Infection led to weight loss and L. interrogans dissemination from blood to urine, and spirochetes were detected in blood and urine simultaneously. The infectious dose that led to consistent dissemination to kidney after conjunctival infection was ∼108 leptospires. Interestingly, a lower number of spirochetes appeared to colonize the kidney, given that we quantified ∼105 and ∼10 leptospires per µl of urine and per µg of kidney, respectively. Leptospira-specific IgM and IgG were detected at 15 days postinfection, and isotyping of the Ig subclass showed that the total IgG response switched from an IgG1 response to an IgG3 response after infection with L. interrogans Histological periodic acid-Schiff D staining of infected kidney showed interstitial nephritis, mononuclear cell infiltrates, and reduced size of glomeruli. Quantification of proinflammatory immunomediators in kidney showed that keratinocyte-derived chemokine, macrophage inflammatory protein 2, RANTES, tumor necrosis factor alpha, gamma interferon, and interleukin-10 were upregulated in infected mice. We show that the kinetics of disease progression after infection via the ocular conjunctiva is delayed compared with infection via the standard intraperitoneal route. Differences may be related to the number of L. interrogans spirochetes that succeed in overcoming the natural defenses of the ocular conjunctiva and transit through tissue.

Vertical transmission of bacterial eye infections, Angola, 2011-2012.

To determine transmission rates for neonatal conjunctivitis causative microorganisms in Angola, we analyzed 312 endocervical and 255 conjunctival samples from mothers and newborns, respectively, during 2011-2012. Transmission rates were 50% for Chlamydia trachomatis and Neisseria gonorrhoeae and 10.5% for Mycoplasma genitalium. Possible pathogenic effects of M. genitalium in children's eyes are unknown.

Feeder use predicts both acquisition and transmission of a contagious pathogen in a North American songbird.

Individual heterogeneity can influence the dynamics of infectious diseases in wildlife and humans alike. Thus, recent work has sought to identify behavioural characteristics that contribute disproportionately to individual variation in pathogen acquisition (super-receiving) or transmission (super-spreading). However, it remains unknown whether the same behaviours enhance both acquisition and transmission, a scenario likely to result in explosive epidemics. Here, we examined this possibility in an ecologically relevant host-pathogen system: house finches and their bacterial pathogen, Mycoplasma gallisepticum, which causes severe conjunctivitis. We examined behaviours likely to influence disease acquisition (feeder use, aggression, social network affiliations) in an observational field study, finding that the time an individual spends on bird feeders best predicted the risk of conjunctivitis. To test whether this behaviour also influences the likelihood of transmitting M. gallisepticum, we experimentally inoculated individuals based on feeding behaviour and tracked epidemics within captive flocks. As predicted, transmission was fastest when birds that spent the most time on feeders initiated the epidemic. Our results suggest that the same behaviour underlies both pathogen acquisition and transmission in this system and potentially others. Identifying individuals that exhibit such behaviours is critical for disease management.

Secondary household transmission of conjunctivitis in children.

Among surveyed households, the transmission rate of pediatric conjunctivitis was 12%. Rates did not differ when the index child did or did not use an ophthalmic antibiotic (14% vs 11% [P = 0.6]). Transmission rates were lower than for other infections where children are not routinely excluded from school or daycare.

Deposition of pathogenic Mycoplasma gallisepticum onto bird feeders: host pathology is more important than temperature-driven increases in food intake.

Although ambient temperature has diverse effects on disease dynamics, few studies have examined how temperature alters pathogen transmission by changing host physiology or behaviour. Here, we test whether reducing ambient temperature alters host foraging, pathology and the potential for fomite transmission of the bacterial pathogen Mycoplasma gallisepticum (MG), which causes seasonal outbreaks of severe conjunctivitis in house finches (Haemorhous mexicanus). We housed finches at temperatures within or below the thermoneutral zone to manipulate food intake by altering energetic requirements of thermoregulation. We predicted that pathogen deposition on bird feeders would increase with temperature-driven increases in food intake and with conjunctival pathology. As expected, housing birds below the thermoneutral zone increased food consumption. Despite this difference, pathogen deposition on feeders did not vary across temperature treatments. However, pathogen deposition increased with conjunctival pathology, independently of temperature and pathogen load, suggesting that MG could enhance its transmission by increasing virulence. Our results suggest that in this system, host physiological responses are more important for transmission potential than temperature-dependent alterations in feeding. Understanding such behavioural and physiological contributions to disease transmission is critical to linking individual responses to climate with population-level disease dynamics.

Chlamydophila felis infection. ABCD guidelines on prevention and management.

OVERVIEW: Chlamydophila felis is a Gram-negative bacterium and its primary target is the conjunctiva. The bacterium does not survive outside the host. INFECTION: Transmission requires close contact between cats; ocular secretions are probably the most important body fluid for infection. Most cases occur in cats under 1 year of age. Chlamydophila felis is the infectious organism most frequently associated with conjunctivitis. DISEASE SIGNS: Unilateral ocular disease generally progresses to become bilateral. There can be intense conjunctivitis with extreme hyperaemia of the nictitating membrane, blepharospasm and ocular discomfort. Transient fever, inappetence and weight loss may occur shortly after infection, although most cats remain well and continue to eat. DIAGNOSIS: PCR techniques are now preferred for diagnosing C felis infection. Ocular swabs are generally used. In unvaccinated cats, antibody detection can be used to indicate infection. DISEASE MANAGEMENT: Tetracyclines are generally regarded as the antibiotics of choice. Doxycycline has the advantage of requiring only single daily administration and is given at a dose of 10 mg/kg orally. Vaccination should be considered if there is a history of confirmed chlamydial disease in a shelter. Single housing and routine hygiene measures should suffice to avoid cross-infection. Cats maintained together for longer terms should be vaccinated regularly. In breeding catteries where C felis infection is endemic, the first step should be to treat all cats with doxycycline for at least 4 weeks. Once clinical signs have been controlled, the cats should be vaccinated. VACCINATION RECOMMENDATIONS: Vaccination should be considered for cats at risk of exposure to infection. Vaccination generally begins at 8-10 weeks of age, with a second injection 3-4 weeks later. Annual boosters are recommended for cats at continued risk of exposure.

Comparative infectiousness of three passerine bird species after experimental inoculation with Mycoplasma gallisepticum.

Mycoplasma gallisepticum has been isolated from various species of free-living birds, and we therefore tested the hypothesis that bird species other than the main host, the house finch (Carpodacus mexicanus), could play a role in the epidemiology of the infection. We compared the disease course in the house finch, American goldfinch (Carduelis tristis) and house sparrow (Passer domesticus) after inoculation into the conjunctival sac with M. gallisepticum, and also the degree to which the three species were infectious to other naive house finches. Severity of clinical signs was least in house sparrows, intermediate in American goldfinch and the highest in house finch. House sparrows were only mildly infectious to naive house finches for a short time, whereas American goldfinches remained infectious for up to 49 days post inoculation, although by then there were no physical signs of disease. We conclude that since American goldfinches can be infectious without showing any conjunctivitis, and since they often make long-distance movements, they might play an as yet unsuspected but important role in M. gallisepticum dynamics in house finches.

An outbreak of chlamydiosis in farmed Indopacific crocodiles (Crocodylus porosus).

An outbreak of chlamydiosis was diagnosed in hatchling and juvenile Indopacific crocodiles (Crocodylus porosus) on a crocodile farm in Papua New Guinea. The outbreak was characterised by high mortality with hepatitis and exudative conjunctivitis. The agent appears to have been introduced with live wild-caught crocodiles, which are purchased routinely by the farm. Improved quarantine procedures and treatment with tetracycline led to a rapid reduction of losses on the farm.

An outbreak of conjunctivitis due to atypical Streptococcus pneumoniae.

BACKGROUND: In February 2002, clinicians at the Dartmouth College Health Service recognized an outbreak of conjunctivitis; cultures of conjunctival swabs implicated Streptococcus pneumoniae. An investigation was begun to determine the extent of the outbreak, confirm the cause, identify modes of transmission, and implement control measures. METHODS: Investigators reviewed the health service's data base for diagnoses of conjunctivitis. Viral and bacterial cultures were obtained from ill students. Bile-soluble isolates that were susceptible to ethylhydrocupreine (optochin) and therefore were presumed to be pneumococci underwent serotyping, capsular staining, pulsed-field gel electrophoresis, a DNA probe, and multilocus sequence typing. A cohort study of risk factors was conducted with the use of the Internet. Control measures included distribution of alcohol-based hand gel and messages about prevention. RESULTS: Among 5060 students, 698 (13.8 percent) received a diagnosis of conjunctivitis from January 1, 2002, through April 12, 2002, including 22 percent of first-year students. Presumed pneumococci were isolated from 43.3 percent of conjunctival swabs (110 of 254); viral cultures performed on 85 specimens were negative. DNA probes and multilocus sequence typing confirmed that the organisms were pneumococci, although the bacteria did not have the characteristic capsule. On pulsed-field gel electrophoresis, strains were found to be identical to pneumococci that caused outbreaks of conjunctivitis in other parts of the country in 1980. Analysis of survey data from 1832 students indicated that close contact with a student with conjunctivitis, wearing contact lenses, membership on a sports team, and attending parties at or living in a fraternity or sorority house were associated with conjunctivitis. The rate of diagnosis of conjunctivitis declined after the implementation of control measures and after spring break. CONCLUSIONS: This large outbreak of conjunctivitis on a college campus was caused by an atypical, unencapsulated strain of S. pneumoniae that was identical to strains that had caused outbreaks two decades earlier.

Randomised equivalency trial comparing 2.5% povidone-iodine eye drops and ophthalmic chloramphenicol for preventing neonatal conjunctivitis in a trachoma endemic area in southern Mexico.

AIM: To evaluate the effectiveness of 2.5% povidone-iodine eye drops (PIED) compared with ophthalmic chloramphenicol (OC) for preventing neonatal conjunctivitis. METHODS: 2004 neonates were enrolled from three rural hospitals in a trachoma endemic area. They were randomly assigned to receive either PIED (n = 1024) or OC (n = 974). Infectious conjunctivitis was confirmed by laboratory methods, including specific search for Chlamydia trachomatis by polymerase chain reaction assay. RESULTS: During the first 48 hours after birth, PIED and OC had similar efficacy against bacterial conjunctivitis (95% confidence interval (CI), -0.031 to -0.004; p = 0.01); from day 3 to day 15, PIED was 6% less effective than OC (95% CI, -0.058 to -0.006; p = 0.01); after day 16 there was no significant difference between the groups (95% CI, -0.022 to 0.041; p = 0.57). However, the risk of C trachomatis conjunctivitis was increased in neonates receiving PIED prophylaxis (relative risk = 1.99 (95% CI, 1.07 to 3.71), log-rank p = 0.029). Ocular side effects were rare and self limiting in both groups (p = 0.223). CONCLUSIONS: PIED seems to increase the risk of acquiring chlamydial conjunctivitis in neonates. Additional measures are required to prevent mother to fetus transmission of chlamydial infection during pregnancy, delivery, and after birth.

Spatial spread of an emerging infectious disease: conjunctivitis in House Finches.

In this paper we quantify the rate of spread of the newly emerged pathogen Mycoplasma gallisepticum of the House Finch, Carpodacus mexicanus, in its introduced range. We compare and contrast the rapid, yet decelerating, rate of spread of the pathogen with the slower, yet accelerating rate of spread of the introduced host. Comparing the rate of spread of this pathogen to pathogens in terrestrial mammalian hosts, we see that elevation and factors relating to host abundance restrict disease spread, rather than finding any major effects of discrete barriers or anthropogenic movement. We examine the role of seasonality in the rate of spread, finding that the rate and direction of disease spread relates more to seasonality in host movement than to seasonality in disease prevalence. We conclude that asymptomatic carriers are major transmitters of Mycoplasma gallisepticum into novel locations, a finding which may also be true for many other diseases, such as West Nile Virus and avian influenza.

Further western spread of Mycoplasma gallisepticum infection of house finches.

Mycoplasma gallisepticum, an important pathogen of poultry, especially chickens and turkeys, emerged in 1994 as the cause of conjunctivitis in house finches (Carpodacus mexicanus) in their eastern range of North America. The resulting epidemic of M. gallisepticum conjunctivitis severely decreased house finch abundance and the continuing endemic disease in the eastern range has been associated with repeating seasonal peaks of conjunctivitis and limitation of host populations. Mycoplasma gallisepticum conjunctivitis was first confirmed in the western native range of house finches in 2002 in a Missoula, Montana, population. Herein, we report further western expansion of M. gallisepticum conjunctivitis in the native range of house finches based on positive polymerase chain reaction results with samples from birds captured in 2004 and 2005 near Portland, Oregon.

Controlling contagious bacterial conjunctivitis.

BACKGROUND: Recent outbreaks (epidemics) of Streptococcus pneumoniae conjunctivitis, involving hundreds of patients, underscore the importance of following recommended guidelines to minimize disease transmission. These include the use of antimicrobial agents capable of minimizing patients' symptoms and the duration of the infectious period when disease can be transmitted to others. PURPOSE: To compare the amount of time required forvarious antibiotic solutions to kill S. pneumoniae, a common cause of bacterial conjunctivitis. MATERIALS AND METHODS: Isolates of S. pneumoniae from three patients were exposed to selected ophthalmic antibiotic products: moxifloxacin 0.5%, tobramycin 0.3%, gentamicin 0.3%, and polymyxin B 10,000 IU-trimethoprim 1.0%. The products were diluted 1:100 and 1:1000 for testing. At 15, 30, 60, 120, and 180 minutes after exposure, aliquots of broth were withdrawn, the cells were separated and cultured, and the viable cell count was determined. RESULTS: Moxifloxacin killed actively growing S. pneumoniae faster and to a greater extent than did the other three antibiotic products when tested at concentrations corresponding to tear film concentrations 5 to 10 minutes and 30 to 60 minutes after instillation of the products. CONCLUSIONS: Moxifloxacin killed S. pneumoniae in vitro faster than did the other antibiotics. Consequently, its use should complement other generally accepted measures for minimizing patients' symptoms and limiting the contagiousness of bacterial conjunctivitis. Also, this is consistent with the recommendations of other investigators to prescribe the most recent generation of fluoroquinolone antibiotics for the specific purpose of limiting the spread of bacterial resistance.

[Neonatal conjunctivitis in a hospital at Gran Buenos Aires. Last 5 years up-date]. / Conjuntivitis neonatal en un hospital del Gran Buenos Aires. Situación de los últimos 5 años.

Neonatal conjunctivitis is one of the most important consultation reasons in the first days of life. Causes may be chemical or infectious. Neonatal conjunctivitis study for common microorganisms and Chlamydia trachomatis is being performed at Posadas Hospital since 1995, in a progressive form. The objective of this study was to know the epidemiological situation in the last five years (1999-2003), and to describe the variations detected between two periods, 1995-1998, and 1999-2003. It was observed no change about C. trachomatis prevalence (8%), during all the time in the population studied. With regard to common microorganisms it was showed a decrease in the second period (36.6%) with respect to the first (52.4%). Likely, the causes may be due to changes about sample collection conditions, or to epidemiological variations. The most frequent microorganisms found were: Staphylococcus aureus 69 (27.6%), Streptococcus pneumoniae 68 (27.2%), and Haemophilus influenzae 64 (25.6%). We consider important to evaluate the kind of ocular secretions at the first consultation, which can lead to a symptomatic treatment that will be corroborated or not, according to microbiological results.

Seasonality and wildlife disease: how seasonal birth, aggregation and variation in immunity affect the dynamics of Mycoplasma gallisepticum in house finches.

We examine the role of host seasonal breeding, host seasonal social aggregation and partial immunity in affecting wildlife disease dynamics, focusing on the dynamics of house finch conjunctivitis (Mycoplasma gallisepticum (MG) in Carpodacus mexicanus). This case study of an unmanaged emerging infectious disease provides useful insight into the important role of seasonal factors in driving ongoing disease dynamics. Seasonal breeding can force recurrent epidemics through the input of fresh susceptibles, which will clearly affect a wide variety of wildlife disease dynamics. Seasonal patterns of social aggregation and foraging behaviour could change transmission dynamics. We use latitudinal variation in the timing of breeding, and social systems to model seasonal dynamics of house finch conjunctivitis across eastern North America. We quantify the patterns of seasonal breeding, and social aggregation across a latitudinal gradient in the eastern range of the house finch, supplemented with known field and laboratory information on immunity to MG in finches. We then examine the interactions of these factors in a theoretical model of disease dynamics. We find that both forms of seasonality could explain the dynamics of the house finch-MG system, and that these factors could have important effects on the dynamics of wildlife diseases generally. In particular, while either alone is sufficient to create recurrent cycles of prevalence in a population with an endemic disease, both are required to produce the specific semi-annual pattern of disease prevalence seen in the house finch conjunctivitis system.

Outbreak of erythromycin-resistant staphylococcal conjunctivitis in a newborn nursery.

We investigated an outbreak of erythromycin-resistant Staphylococcus aureus conjunctivitis in a hospital newborn nursery that used erythromycin eye ointment to prevent ophthalmia neonatorum. Cases occurred in 2 clusters; 20 (14%) of 146 infants in the nursery developed conjunctivitis from July through October, 1987; and 5 (7%) of 69 infants in the nursery developed conjunctivitis during April and May, 1988. A case-control study of the first cluster demonstrated that culture-confirmed cases were more likely than controls to have received prophylactic erythromycin eye ointment or their initial bath from one nurse (odds ratio, 9.0; P = 0.01) or to have been delivered by one physician (odds ratio, 12.7; P = 0.03). The nurse was the only staff person to have a nasopharyngeal culture which yielded erythromycin-resistant S. aureus. Control measures, instituted in October, 1987, included using silver nitrate drops instead of erythromycin eye ointment for prophylaxis; however, in January, 1988, the hospital resumed use of erythromycin eye ointment. No additional cases were identified until mid-April, 1988, when the second cluster of cases occurred. At that time the hospital reinstituted the use of silver nitrate and no additional cases were identified. This investigation illustrates the potential for conjunctival infection with an antimicrobial-resistant pathogen when antimicrobials are used to prevent ophthalmia neonatorum.

Conjunctivitis due to Chlamydophila felis (Chlamydia psittaci feline pneumonitis agent) acquired from a cat: case report with molecular characterization of isolates from the patient and cat.

Conjunctivitis due to Chlamydiaceae other than Chlamydia trachomatis is rarely reported because of infrequent occurrence or inadequate investigation. A case of chronic non-trachomatis chlamydial conjunctivitis is described. After full clinical information was supplied to the laboratory, a non-trachomatis chlamydia was recovered from the patient's eye. This organism, and a subsequent isolate from one of the patient's cats, were shown to be indistinguishable examples of the recently described species Chlamydophila felis. The infection was most likely acquired from the patient's cats. A prolonged course of doxycycline was required to eradicate the infection.