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.

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.

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.

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.

Infectious conjunctivitis caused by Pseudomonas aeruginosa isolated from a bathroom.

BACKGROUND: The elucidation of the routes of transmission of a pathogen is crucial for the prevention of infectious diseases caused by bacteria that are not a resident in human tissue. The purpose of this report is to describe a case of suture-related conjunctivitis caused by Pseudomonas aeruginosa for which we identified the transmission route using pulsed-field gel electrophoresis (PFGE). CASE PRESENTATION: A 38-year-old man, who had undergone surgery for glaucoma 2 years ago previously, presented with redness, discomfort, and mucopurulent discharge in the right eye. A 9-0 silk suture had been left on the conjunctiva. A strain of P. aeruginosa was isolated from a culture obtained from the suture, and the patient was therefore diagnosed with suture-related conjunctivitis caused by P. aeruginosa. The conjunctivitis was cured by the application of an antimicrobial ophthalmic solution and removal of the suture. We used PFGE to survey of the indoor and outdoor environments around the patient's house and office in order to elucidate the route of transmission of the infection. Three strains of P. aeruginosa were isolated from the patient's indoor environment, and the isolate obtained from the patient's bathroom was identical to that from the suture. CONCLUSION: The case highlights the fact that an indoor environmental strain of P. aeruginosa can cause ocular infections.

Can American goldfinches function as reservoirs for Mycoplasma gallisepticum?

We performed experiments to test if American Goldfinches (Spinus tristis) could be a competent reservoir for Mycoplasma gallisepticum and play a role in the epidemic spread of mycoplasmal conjunctivitis among House Finches (Carpodacus mexicanus) in North America. We infected one of two individuals housed together in a cage and determined if transmission occurred to the second bird. Probability of transmission between an American Goldfinch and a House Finch (in either direction) was similar to that between two House Finches. In a second experiment small groups of birds (6-8) were housed in large aviaries. Two source birds were inoculated with M. gallisepticum, and transmission to the naive birds in the aviary was recorded. Transmission occurred among House Finches, among American Goldfinches, and from House Finches to American Goldfinches. Transmission was more likely between House Finches than among American Goldfinches, and between House Finches and American Goldfinches. We conclude that American Goldfinches are a competent reservoir for Mycoplasma gallisepticum and could have played a role in the spread of the epidemic as they are more migratory than House Finches.

Mycoplasma sturni from a California House Finch with conjunctivitis did not cause disease in experimentally infected House Finches.

Mycoplasma gallisepticum conjunctivitis emerged in 1994 as a disease of free-ranging House Finches (Carpodacus mexicanus) in North America and has also been isolated from other songbirds with conjunctivitis. A key feature for the successful study of natural and experimental disease has been the apparent, very-high correlation between characteristic eye lesions and M. gallisepticum. Mycoplasma sturni was originally isolated from an adult European Starling (Sturnus vulgaris) with bilateral conjunctivitis and has since been reported in a relatively small number of other avian species, but not in House Finches. We identified as M. sturni a mycoplasma isolate from a California House Finch with conjunctivitis. However, experimental infection of House Finches with the M. sturni isolate failed to reproduce the disease. Therefore, M. gallisepticum remains the primary known cause of conjunctivitis in House Finches.

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.

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.

Management strategies for acute infective conjunctivitis in primary care: a systematic review.

A systematic review of the literature on all aspects of the management of acute infective conjunctivitis is undertaken. Acute infective conjunctivitis is a common presentation in primary healthcare. It is usually a mild condition and serious complications are rare. Clinical signs are a poor discriminator of bacterial and viral causes. Studies of treatment show that there is a high rate of clinical cure without any treatment (65% within 2-5 days). Treatment with topical antibiotics improves the rate of clinical recovery and this is more marked in the first 2-5 days after presentation (number needed to treat [NNT] = 6), but less by 6-10 days (NNT = 13). Studies comparing treatment with different antibiotics do not demonstrate that any one antibiotic is superior; the choice of antibiotic should be based on consideration of cost and bacterial resistance. The present practice of prescribing antibiotics to most cases is not necessary.

Experimental evidence for transmission of Mycoplasma gallisepticum in house finches by fomites.

Ever since Mycoplasma gallisepticum emerged among house finches in North America, it has been suggested that bird aggregations at feeders are an important cause of the epidemic of mycoplasmal conjunctivitis because diseased birds could deposit droplets of pathogen onto the feeders and thereby promote indirect transmission by fomites. In this paper we bring the first experimental evidence that such transmission (bird-to-feeder-to-bird) does actually take place. House finches infected via this route, however, developed only mild disease and recovered much more rapidly than birds infected from the same source birds but directly into the conjunctiva. While it is certainly probable that house finch aggregations at artificial feeders enhance pathogen transmission, to some degree transmission of M. gallisepticum by fomites may serve to immunize birds against developing more severe infections. Some such birds develop M. gallisepticum antibodies, providing indication of an immune response, although no direct evidence of protection.

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.

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.

[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.