Large Community Outbreak of Legionnaires Disease Potentially Associated with a Cooling Tower - Napa County, California, 2022.

Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11 and 12, 2022, Napa County Public Health (NCPH) in California received reports of three positive urinary antigen tests for Legionella pneumophila serogroup 1 in the town of Napa. By July 21, six Legionnaires disease cases had been confirmed among Napa County residents, compared with a baseline of one or two cases per year. NCPH requested assistance from the California Department of Public Health (CDPH) and CDC to aid in the investigations. Close temporal and geospatial clustering permitted a focused environmental sampling strategy of high-risk facilities which, coupled with whole genome sequencing results from samples and investigation of water system maintenance, facilitated potential linking of the outbreak with an environmental source. NCPH, with technical support from CDC and CDPH, instructed and monitored remediation practices for all environmental locations that tested positive for Legionella. The investigation response to this community outbreak illustrates the importance of interdisciplinary collaboration by public health agencies, laboratory support, timely communication with the public, and cooperation of managers of potentially implicated water systems. Timely identification of possible sources, sampling, and remediation of any facility testing positive for Legionella is crucial to interrupting further transmission.

Injuries and Traumatic Psychological Exposures Associated with the South Napa Earthquake - California, 2014.

On August 24, 2014, at 3:20 a.m., a magnitude 6.0 earthquake struck California, with its epicenter in Napa County (1). The earthquake was the largest to affect the San Francisco Bay area in 25 years and caused significant damage in Napa and Solano counties, including widespread power outages, five residential fires, and damage to roadways, waterlines, and 1,600 buildings (2). Two deaths resulted (2). On August 25, Napa County Public Health asked the California Department of Public Health (CDPH) for assistance in assessing postdisaster health effects, including earthquake-related injuries and effects on mental health. On September 23, Solano County Public Health requested similar assistance. A household-level Community Assessment for Public Health Emergency Response (CASPER) was conducted for these counties in two cities (Napa, 3 weeks after the earthquake, and Vallejo, 6 weeks after the earthquake). Among households reporting injuries, a substantial proportion (48% in Napa and 37% in western Vallejo) reported that the injuries occurred during the cleanup period, suggesting that increased messaging on safety precautions after a disaster might be needed. One fifth of respondents overall (27% in Napa and 9% in western Vallejo) reported one or more traumatic psychological exposures in their households. These findings were used by Napa County Mental Health to guide immediate-term mental health resource allocations and to conduct public training sessions and education campaigns to support persons with mental health risks following the earthquake. In addition, to promote community resilience and future earthquake preparedness, Napa County Public Health subsequently conducted community events on the earthquake anniversary and provided outreach workers with psychological first aid training.

Experimental infection of cats with Afipia felis and various Bartonella species or subspecies.

Based upon prior studies, domestic cats have been shown to be the natural reservoir for Bartonella henselae, Bartonella clarridgeiae and Bartonella koehlerae. However, other Bartonella species, such as Bartonella vinsonii subsp. berkhoffii, Bartonella quintana or Bartonella bovis (ex weissii) have been either isolated from or Bartonella DNA sequences PCR amplified and sequenced. In the late 1980s, before B. henselae was confirmed as the etiological agent of cat scratch disease, Afipia felis had been proposed as the causative agent. In order to determine the feline susceptibility to A. felis, B. vinsonii subsp. berkhoffii, Bartonella rochalimae, B. quintana or B. bovis, we sought to detect the presence of bacteremia and seroconversion in experimentally-inoculated cats. Most of the cats seroconverted, but only the cats inoculated with B. rochalimae became bacteremic, indicating that cats are not natural hosts of A. felis or the other Bartonella species or subspecies tested in this study.

Experimental infection of dogs with various Bartonella species or subspecies isolated from their natural reservoir.

Dogs can be infected by a wide variety of Bartonella species. However, limited data is available on experimental infection of dogs with Bartonella strains isolated from domestic animals or wildlife. We report the inoculation of six dogs with Bartonella henselae (feline strain 94022, 16S rRNA type II) in three sets of two dogs, each receiving a different inoculum dose), four dogs inoculated with B. vinsonii subsp. berkhoffii type I (ATCC strain, one mongrel dog) or type II (coyote strain, two beagles and one mongrel) and B. rochalimae (coyote strain, two beagles). None of the dogs inoculated with B. henselae became bacteremic, as detected by classical blood culture. However, several dogs developed severe necrotic lesions at the inoculation site and all six dogs seroconverted within one to two weeks. All dogs inoculated with the B. v. berkhoffii and B. rochalimae strains became bacteremic at levels comparable to previous experimental infections with either a dog isolate or a human isolate. Our data support that dogs are likely accidental hosts for B. henselae, just like humans, and are efficient reservoirs for both B. v. berkhoffii and B. rochalimae.

Bartonella rochalimae in raccoons, coyotes, and red foxes.

To determine additional reservoirs for Bartonella rochalimae, we examined samples from several wildlife species. We isolated B. rochalimae from 1 red fox near Paris, France, and from 11 raccoons and 2 coyotes from California, USA. Co-infection with B. vinsonii subsp. berkhoffii was documented in 1 of the coyotes.

Bartonella quintana in body lice and head lice from homeless persons, San Francisco, California, USA.

Bartonella quintana is a bacterium that causes trench fever in humans. Past reports have shown Bartonella spp. infections in homeless populations in San Francisco, California, USA. The California Department of Public Health in collaboration with San Francisco Project Homeless Connect initiated a program in 2007 to collect lice from the homeless to test for B. quintana and to educate the homeless and their caregivers on prevention and control of louse-borne disease. During 2007-2008, 33.3% of body lice-infested persons and 25% of head lice-infested persons had lice pools infected with B. quintana strain Fuller. Further work is needed to examine how homeless persons acquire lice and determine the risk for illness to persons infested with B. quintana-infected lice.

Dogs are more permissive than cats or guinea pigs to experimental infection with a human isolate of Bartonella rochalimae.

Bartonella rochalimae was first isolated from the blood of a human who traveled to Peru and was exposed to multiple insect bites. Foxes and dogs are likely natural reservoirs for this bacterium. We report the results of experimental inoculation of two dogs, five cats and six guinea pigs with the only human isolate of this new Bartonella species. Both dogs became bacteremic for 5-7 weeks, with a peak of 10(3)-10(4) colony forming units (CFU)/mL blood. Three cats had low bacteremia levels (< 200 CFU/mL) of 6-8 weeks' duration. One cat that remained seronegative had two bacterial colonies isolated at a single culture time point. A fifth cat never became bacteremic, but seroconverted. None of the guinea pigs became bacteremic, but five seroconverted. These results suggest that dogs could be a reservoir of this strain of B. rochalimae, in contrast to cats and guinea pigs.

Zoonotic Bartonella species in fleas collected on gray foxes (Urocyon cinereoargenteus).

Bartonella spp. are fastidious, gram-negative, rod-shaped bacteria and are usually vector-borne. However, the vector has not been definitively identified for many recently described species. In northern California, gray foxes (Urocyon cinereoargenteus) are infected with two zoonotic Bartonella species, B. rochalimae and B. vinsonii subsp. berkhoffii. Fleas (range 1-8 fleas per fox) were collected from 22 (41.5%) of 54 gray foxes from urban and backcountry zones near Hoopa, California. The flea species were determined, and DNA was individually extracted to establish the Bartonella species harbored by these fleas. Of the 108 fleas collected, 99 (92%) were identified as Pulex simulans. Overall, 39% (42/108) of the fleas were polymerase chain reaction (PCR)-positive for Bartonella, with B. rochalimae and B. vinsonii subsp. berkhoffii identified in 34 (81%) and 8 (19%) of the PCR-positive fleas, respectively. There was no difference between the prevalence of Bartonella spp. in P. simulans for the urban and backcountry zones. Fourteen (64%) of the 22 foxes were Bartonella bacteremic at one or more of the capture dates. In 10 instances, both the foxes and the fleas collected from them at the same blood collection were Bartonella-positive. B. rochalimae was the predominant species identified in both foxes and fleas. The competency of Pulex fleas as a vector of B. rochalimae has not been confirmed and will need to be demonstrated experimentally. Pulex spp. fleas readily feed on humans and may represent a source of human exposure to zoonotic species of Bartonella.

Infective endocarditis in a dog and the phylogenetic relationship of the associated "Bartonella rochalimae" strain with isolates from dogs, gray foxes, and a human.

The first case of canine endocarditis caused by "Bartonella rochalimae" is reported. By PCR-restriction fragment length polymorphism, sequence, and phylogenetic analyses, Bartonella isolates from a dog with endocarditis, 22 gray foxes, and three dogs, described as B. clarridgeiae like, were confirmed to belong to the new species "B. rochalimae," suggesting canids as the natural reservoir.

Seroprevalence of Bartonella spp. in the endangered island fox (Urocyon littoralis).

Bartonella clarridgeiae-like strains, presently B. rochalimae, were isolated in gray foxes (Urocyon cinereoargenteus) in mainland California. The objective of this study was to investigate the presence of Bartonella infection in the endangered island fox (Urocyon littoralis) found only on the Channel Islands off the Californian coast. Between 2001 and 2004, 263 serum samples were collected. Antibodies against Bartonella vinsonii subsp. berkhoffii (Bvb) and B. clarridgeiae (Bc) were detected using an immuno-fluorescence antibody test. Sixty-eight (25.8%) and 73 (27.7%) foxes were positive for Bvb and Bc, respectively. Seroprevalence was the highest on Santa Cruz Island (n=36, Bvb=80.5%; Bc=86.1%) and Santa Rosa Island (n=38, Bvb=52.6%; Bc=65.8%). On San Miguel and San Clemente Islands, seroprevalence for Bvb was 20% and 17.3% respectively, and 0% and 21.3% for Bc. Prevalence ranged between 0% and 5.1% on San Nicolas and Santa Catalina Islands. Foxes from Santa Rosa and Santa Cruz Islands were 17.5 times and 31.5 times as likely to be seropositive for Bvb and Bc than foxes from the other islands (95% confidence interval [95% CI]=8.5, 36.7; 14.4, 70.2). There were no statistically significant differences for presence of Bartonella antibodies by sex, age, origin (captive vs. wild) or year of blood collection. This is the first report of exposure to Bartonella in the island fox population. Further studies are necessary to isolate these bacteria from foxes and determine factors associated with presence or absence of Bartonella species on specific islands.

Development time of Culex mosquitoes in stormwater management structures in California.

A widely recommended strategy to minimize mosquito production in structural stormwater Best Management Practices (BMPs) is to ensure they hold captured water for no more than 72 h. However, this standard may be overly conservative for many mosquito species found in urban environments and may impede or prevent the capacity of BMPs to fulfill more stringent water quality standards in environmentally sensitive areas. Egg-to-pupa development of Culex tarsalis, Cx. pipiens, and Cx. quinquefasciatus were examined during July, August, and September 2006 in stormwater management basins and in water collected from these basins in 3 climatically distinct regions of California: the Lake Tahoe Basin, Sacramento Valley, and Los Angeles Basin. The observed minimum times to pupal development were 6 days for Cx. tarsalis and Cx. quinquefasciatus and 8 days for Cx. pipiens. Multiple linear regression models were used to estimate minimum predicted development times under optimal conditions for each region. The results suggest that water residence times of up to 96 h will not significantly increase the potential for Culex mosquito production in stormwater BMPs in the 3 regions included in this study.

Gray foxes (Urocyon cinereoargenteus) as a potential reservoir of a Bartonella clarridgeiae-like bacterium and domestic dogs as part of a sentinel system for surveillance of zoonotic arthropod-borne pathogens in northern California.

Two species of Bartonella, a novel Bartonella clarridgeiae-like bacterium and B. vinsonii subsp. berkhoffii, were isolated from rural dogs and gray foxes in northern California. A novel B. clarridgeiae-like species was isolated from 3 (1.7%) of 182 dogs and 22 (42%) of 53 gray foxes, while B. vinsonii subsp. berkhoffii was isolated from 1 dog (0.5%) and 5 gray foxes (9.4%). PCR and DNA sequence analyses of the citrate synthase (gltA) gene and the 16S-23S intergenic spacer region suggested that strains infecting dogs and gray foxes were identical. Fifty-four dogs (29%) and 48 gray foxes (89%) had reciprocal titers of antibodies against Bartonella spp. of > or =64. The high prevalence of bacteremia and seroreactivity to Bartonella spp. in gray foxes suggests that they may act as a reservoir species for the B. clarridgeiae-like species in this region. Domestic dogs were also tested for other arthropod-borne infectious agents. Fifty-one dogs (28%) were positive for Dirofilaria immitis antigen, seventy-four (40%) were seroreactive to Anaplasma phagocytophilum, and five (2.7%) were seropositive for Yersinia pestis. Fourteen dogs (7.6%) were PCR positive for A. phagocytophilum. Polytomous logistic regression models were used to assess the association of Bartonella antibody titer categories with potential risk factors and the presence of other vector-borne agents in domestic dogs. Older dogs were more likely to be seroreactive to Bartonella spp. There was no association between the exposure of dogs to Bartonella and the exposure of dogs to A. phagocytophilum in this study.

Bartonella henselae infection in splenectomized domestic cats previously infected with hemotropic Mycoplasma species.

Cat scratch disease is caused by Bartonella henselae and the domestic cat represents its main reservoir. In immunocompromised patients, infection with B. henselae is characterized by more severe clinical forms than in non-immunocompromised individuals. The objective of the present study was to investigate the characteristics of B. henselae (Houston-I strain) infection in four splenectomized and three non-splenectomized cats, five of which were chronically infected with 'Candidatus Mycoplasma haemominutum'. No major clinical signs were observed in either group of cats. Cats in both splenectomized and non-splenectomized groups became bacteremic within a week post-inoculation. Although bacteremia was on average 10 days longer in the splenectomized cats, that difference was not statistically significant (P=0.72). In both groups, the level of bacteremia peaked within the same time frame; however, the level of bacteremia was about 10-fold higher in the splenectomized cats (P=0.007). Such a difference could be associated with a reduced immune response to the infection, especially a reduced ability to phagocytize Bartonella organisms in the splenectomized cats. Concurrent infection with 'Candidatus M. haemominutum' did not appear to alter the course of infection.

Bartonella infection in domestic cats and wild felids.

Bartonella are vector-borne, fastidious Gram-negative bacteria causing persistent bacteremia in their reservoir hosts. Felids represent a major reservoir for several Bartonella species. Domestic cats are the main reservoir of B. henselae, the agent of cat-scratch disease. Prevalence of infection is highest in warm and humid climates that are optimal for the survival of cat fleas, as fleas are essential for the transmission of the infection. Flea feces are the likely infectious substrate. Prevalence of B. henselae genotypes among cat populations varies worldwide. Genotype Houston I is more prevalent in the Far East and genotype Marseille is dominant in western Europe, Australia, and the western United States. Cats are usually asymptomatic, but uveitis, endocarditis, neurological signs, fever, necrotic lesions at the inoculation site, lymphadenopathy, and reproductive disorders have been reported in naturally or experimentally infected cats. Domestic cats are also the reservoir of B. clarridgeiae and co-infection has been demonstrated. B. koehlerae has been isolated from domestic cats, and was identified in cat fleas and associated with a human endocarditis case. B. bovis was isolated from a few cats in the United States and B. quintana DNA was recently identified in a cat tooth. Bartonella spp. have also been isolated from free-ranging and captive wild felids from North America and Africa. Whereas, B. henselae was identified in African lions and a cheetah, some strains specific to these wild cats have also been identified, leading to the concept of a B. henselae group including various subspecies, as previously described for B. vinsonii.

Antibodies to Bartonella vinsonii subsp. Berkhoffii in Moroccan dogs.

Bartonella vinsonii subsp. berkhoffii is a fastidious microorganism that has been recognized as an emerging human and canine pathogen. We report for the first time on the prevalence of antibodies to B. vinsonii subsp. berkhoffii in domestic dogs from Morocco. The overall seroprevalence was 38% (56 of 147 dogs tested). Most of the seropositive dogs were stray dogs from Rabat (36%, 8 of 22) and Khenifra (47%, 47 of 101). Antibodies against B. vinsonii subsp. berkhoffii were found infrequently among pet dogs from Rabat (4%, 1 of 24).

A Bartonella vinsonii berkhoffii typing scheme based upon 16S-23S ITS and Pap31 sequences from dog, coyote, gray fox, and human isolates.

Since the isolation of Bartonella vinsonii subspecies berkhoffii from a dog with endocarditis in 1993, this organism has emerged as an important pathogen in dogs and as an emerging pathogen in people. Current evidence indicates that coyotes, dogs and gray foxes potentially serve as reservoir hosts. Based upon sequence differences within the 16S-23S ITS region and Pap31 gene, we propose a classification scheme that divides B. vinsonii subsp. berkhoffii isolates into four distinct types. Two conserved sequences, of 37 and 18 bp, respectively, are differentially present within the ITS region of each of the four B. vinsonii subsp. berkhoffii types. To date, B. vinsonii berkhoffii types I, II, and III have been identified in the US, type III in Europe and type IV in Canada. Based upon the proposed genotyping scheme, the geographic distribution of B. vinsonii berkhoffii types needs to be more thoroughly delineated in future molecular epidemiological studies involving Bartonella infection in coyotes, dogs, gray foxes, human beings and potentially other animals or in arthropod vectors. Strain typing may help to better define the reservoir potential, carriership patterns, modes of transmission, and geographic distribution for each B. vinsonii berkhoffii type.

Seroprevalence of antibodies against Bartonella species and evaluation of risk factors and clinical signs associated with seropositivity in dogs.

OBJECTIVE: To determine the seroprevalence of antibodies against Bartonella spp in a population of sick dogs from northern California and identify potential risk factors and clinical signs associated with seropositivity. SAMPLE POPULATION: Sera from 3,417 dogs. PROCEDURE: Via an ELISA, sera were analyzed for antibodies against Bartonella vinsonii subsp berkhoffii, Bartonella clarridgeiae, and Bartonella henselae; test results were used to classify dogs as seropositive (mean optical density value > or = 0.350 for B henselae or > or = 0.300 for B clarridgeiae or B vinsonii subsp berkhoffi) or seronegative. Overall, 305 dogs (102 seropositive and 203 seronegative dogs) were included in a matched case-control study. RESULTS: 102 of 3,417 (2.99%) dogs were seropositive for > or = 1 species of Bartonella. Of these, 36 (35.3%) had antibodies against B henselae only, 34 (33.3%) had antibodies against B clarridgeiae only, 2 (2.0%) had antibodies against B vinsonii subsp berkhoffii only, and 30 (29.4%) had antibodies against a combination of those antigens. Compared with seronegative dogs, seropositive dogs were more likely to be herding dogs and to be female, whereas toy dogs were less likely to be seropositive. Seropositive dogs were also more likely to be lame or have arthritis-related lameness, nasal discharge or epistaxis, or splenomegaly. CONCLUSIONS AND CLINICAL RELEVANCE: Only a small percentage of dogs from which serum samples were obtained had antibodies against Bartonella spp. Breed appeared to be an important risk factor for seropositivity. Bartonella infection should be considered in dogs with clinical signs of lameness, arthritis-related lameness, nasal discharge or epistaxis, or splenomegaly.

Factors associated with the rapid emergence of zoonotic Bartonella infections.

Within the last 15 years, several bacteria of the genus Bartonella were recognized as zoonotic agents in humans and isolated from various mammalian reservoirs. Based on either isolation of the bacterium or PCR testing, eight Bartonella species or subspecies have been recognized as zoonotic agents, including B. henselae, B. elizabethae, B. grahamii, B. vinsonii subsp. arupensis, B. vinsonii subsp. berkhoffii, B. grahamii, B. washoensis and more recently B. koehlerae. The present manuscript reviews the factors associated with the emergence of these zoonotic pathogens, including better diagnostic tools and methods to identify these fastidious bacteria, host immunosuppression (caused by infectious agents, cancer, aging or induced by immunosuppressive drugs), the interaction of co-infection by several infectious agents that may enhanced the pathogenecity of these bacteria, increased outdoor activity leading to exposure to wildlife reservoirs or vectors, poverty and low income associated with infestation by various ectoparasites, such as body lice and finally the dispersal of Bartonellae around the world. Furthermore, a description of the main epidemiological and clinical features of zoonotic Bartonellae is given. Finally, the main means for diagnosis, treatment and prevention of these diseases are presented.

Runella zeae sp. nov., a novel gram-negative bacterium from the stems of surface-sterilized Zea mays.

A Gram-negative bacterium, designated NS12(T), was previously isolated from duplicate treatments of surface-sterilized Zea mays stems. The plants were grown in synthetic soil under greenhouse conditions and watered with fertilizer containing no nitrogen. Strain NS12(T) was not isolated from plants watered with the standard level or 20% (w/v) of the standard level of nitrogen. Cells were bent rods that formed chains of irregular shapes in R2A broth. Unlike its closest described relative Runella slithyformis, strain NS12(T) fermented glucose and sucrose. The G+C content was 49 mol%. Phylogenetic analysis of the 16S rRNA gene showed that the strain was a member of the domain Bacteria and is most closely related to R. slithyformis, a member of the Flexibacter group within the Cytophaga-Flexibacter-Bacteroides phylum. Phenotypic and genotypic analyses indicated that strain NS12(T) could not be assigned to any recognized species; therefore a new species designated Runella zeae sp. nov. is proposed, for which NS12(T) ( = ATCC BAA-293(T) = LMG 21438(T)) is the type strain.