BACKGROUND: The Centers for Disease Control and Prevention (CDC) recommends that all women with a stillbirth have a syphilis test after delivery. Our study seeks to evaluate adherence to CDC guidelines for syphilis screening among women with a stillbirth delivery. METHODS: We used data recorded in electronic health records for women who gave birth between January 1, 2014, and December 31, 2016. Patients were included if they were 18 to 44 years old and possessed an International Classification of Diseases, Ninth Revision or Tenth Revision, Clinical Modification diagnosis of stillbirth. Stillbirth diagnoses were confirmed through a random sample of medical chart reviews. To evaluate syphilis screening, we estimated the proportion of women who received syphilis testing within 300 days before stillbirth, women who received syphilis testing within 30 days after a stillbirth delivery, and women who received syphilis testing both before and after stillbirth delivery. RESULTS: We identified 1111 stillbirths among a population of 865,429 unique women with encounter data available from electronic health records. Among a sample of 127 chart-reviewed cases, only 35 (27.6%) were confirmed stillbirth cases, 45 (35.4%) possible stillbirth cases, 39 (30.7%) cases of miscarriage, and 8 (6.3%) cases of live births. Among confirmed stillbirth cases, 51.4% had any syphilis testing conducted, 31.4% had testing before their stillbirth delivery, 42.9% had testing after the delivery, and only 22.9% had testing before and after delivery. CONCLUSIONS: A majority of women with a stillbirth delivery do not receive syphilis screening adherent to CDC guidelines. Stillbirth International Classification of Diseases codes do not accurately identify cases of stillbirth.

BACKGROUND: While researchers seek to use administrative health data to examine outcomes for individuals with sexually transmitted infections, the ICD-CM-10 codes used to identify persons with chlamydia and gonorrhea have not been validated. Objectives were to determine the validity of using ICD-10-CM codes to identify individuals with chlamydia and gonorrhea. METHODS: We utilized data from electronic health records gathered from public and private health systems from October 1, 2015 to December 31, 2016. Patients were included if they were aged 13-44 years and received either 1) laboratory testing for chlamydia or gonorrhea or 2) an ICD-10-CM diagnosis of chlamydia, gonorrhea, or an unspecified STI. To validate ICD-10-CM codes, we calculated positive and negative predictive values, sensitivity, and specificity based on the presence of a laboratory test result. We further examined the timing of clinical diagnosis relative to laboratory testing. RESULTS: The positive predictive values for chlamydia, gonorrhea, and unspecified STI ICD-10-CM codes were 87.6%, 85.0%, and 32.0%, respectively. Negative predictive values were high (>92%). Sensitivity for chlamydia diagnostic codes was 10.6% and gonorrhea was 9.7%. Specificity was 99.9% for both chlamydia and gonorrhea. The date of diagnosis occurred on or after the date of the laboratory result for 84.8% of persons with chlamydia, 91.9% for gonorrhea, and 23.5% for unspecified STI. CONCLUSIONS: Disease specific ICD-10-CM codes accurately identify persons with chlamydia and gonorrhea. However, low sensitivities suggest that most individuals could not be identified in administrative data alone without laboratory test results.

Wildland firefighters are exposed to numerous noise sources that may be hazardous to their hearing. This study examined the noise exposure profiles for 264 wildland firefighters across 15 job categories. All 264 firefighters completed questionnaires to assess their use of hearing protection devices, enrollment in hearing conservation programs, and their overall perception of their noise exposure. Roughly 54% of firefighters' noise exposures exceeded the National Institute for Occupational Safety and Health recommended exposure limit of 85 decibels, A-weighted, over 8 hr, and 32% exceeded the Occupational Safety and Health Administration permissible exposure limit of 90 decibels, A-weighted, over 8 hr. Questionnaire results indicated good agreement between noise exposures and firefighters' perceptions of the noise hazard. Approximately 65% reported that they used some form of hearing protection; however, only 19% reported receiving any proper training regarding the use of hearing protection devices, with the majority of those firefighters relying on earplugs, including electronic and level-dependent earplugs, over earmuffs or other forms of hearing protectors. The results also suggest that improved communication and situational awareness play a greater role in the consistent use of hearing protection devices than other factors such as risk of developing noise-induced hearing loss. The study highlighted the challenges facing wildland firefighters and their management and the need for a comprehensive wildland fire agencies' hearing conservation program especially for firefighters who were exempt based on their occupational designations.

Carbon monoxide (CO) exposure levels encountered by wildland firefighters (WLFs) throughout their work shift can change considerably within a few minutes due to the varied tasks that are performed and the changing environmental and fire conditions encountered throughout the day. In a U.S. Forest Service study during the 2009-2012 fire seasons, WLFs from 57 different fires across the U.S. were monitored for CO using CO data-logging detectors while an observer recorded worker tasks, fire characteristics, and environmental conditions at scheduled intervals. Exposures to CO for 735 WLF's work shifts were analyzed to assess the effect of variations among work tasks, fire characteristics, and environmental conditions. Geometric mean full shift time-weighted averages were low at 2.4 parts per million (ppm) and average length of work shift was 11 hr and 15 min. The task with the highest mean CO exposure was sawyer/swamper at 6.8 ppm; workers performing that task had an estimated 9 times higher odds of a having a 1-min CO measurement exceeding 25 ppm than the referent pump task (OR = 8.89, 95% CI = 1.97, 40.24). After adjusting CO exposure limits for shift length, elevation, and work level, 2% and 4% of the WLF's work shifts exceeded the National Institute for Occupational Safety and Health's recommended exposure level and the American Conference of Governmental Industrial Hygienist's threshold limit value, respectively. In regression modeling, variables that were significantly associated with elevated levels of CO exposure included: task, fuel model, wind orientation, crew type, relative humidity, type of attack, and wind speed. In the absence of instruments such as CO detectors that can determine and alert WLFs to elevated CO levels, recognition of the conditions that lead to elevated levels of CO exposure can assist WLFs to effectively use administrative controls, such as work rotations, to minimize exposures.

Despite dramatic global progress with implementing prevention of mother-to-child HIV transmission (PMTCT) programs, there were 160,000 new pediatric HIV infections in 2016. More than 50% of infant HIV infections now occur in the postpartum period, reflecting the relatively high coverage of interventions in the antenatal period and the need for greater attention to the breastfeeding mother and her HIV-exposed infant (HEI). Early diagnosis and treatment are critical to prevent morbidity and mortality in HIV-infected children; however, early infant HIV testing rates remain low in most high HIV-burden countries. Furthermore, systematic retention and follow-up of HEI in the postpartum period and ascertainment of final HIV status remain major program gaps. Despite multiple calls to action to improve infant HIV testing rates, progress has been marginal due to a lack of focus on the critical health care needs of HEI coupled with health system barriers that result in fragmented services for HIV-infected mothers and their families. In this paper, we describe the available evidence on the health outcomes of HEI, define a comprehensive care package for HEI that extends beyond early HIV testing, and describe successful examples of integrated services for HEI.

Rapid disease progression and associated opportunistic infections contribute to high mortality rates among children aged <15 years with human immunodeficiency virus (HIV) infection (1). Antiretroviral therapy (ART) has decreased childhood HIV-associated morbidity and mortality rates over the past decade (2). As accumulating evidence revealed lower HIV-associated mortality with early ART initiation, the World Health Organization (WHO) guidelines broadened ART eligibility for children with HIV infection (2). Age at ART initiation for children with HIV infection expanded sequentially in the 2010, 2013, and 2016 WHO guidelines to include children aged <2, <5, and <15 years, respectively, regardless of clinical or immunologic status (3-5). The United States President's Emergency Plan for AIDS Relief (PEPFAR) has supported ART for children with HIV infection since 2003 and, informed by the WHO guidelines and a growing evidence base, PEPFAR-supported countries have adjusted their national pediatric guidelines. To understand the lag between guideline development and implementation, as well as the ART coverage gap, CDC assessed national pediatric HIV guidelines and analyzed Joint United Nations Programme on HIV and AIDS (acquired immunodeficiency syndrome; UNAIDS) data on children aged <15 years with HIV infection and the numbers of these children on ART. Timeliness of WHO pediatric ART guideline adoption varied by country; >50% of children with HIV infection are not receiving ART, underscoring the importance of strengthening case finding and linkage to HIV treatment in pediatric ART programs.

INTRODUCTION: With the rapid scale-up of antiretroviral treatment (ART) in the "Treat All" era, there has been increasing emphasis on using differentiated models of HIV service delivery. The gaps within the clinical cascade for mothers and their infants suggest that current service delivery models are not meeting families' needs and prompt re-consideration of how services are provided. This article will explore considerations for differentiated care and encourage the ongoing increase of ART coverage through innovative strategies while also addressing the unique needs of mothers and infants. DISCUSSION: Service delivery models should recognize that the timing of the mother's HIV diagnosis is a critical aspect of determining eligibility. Women newly diagnosed with HIV require a more intensive approach so that adequate counselling and monitoring of ART initiation and response can be provided. Women already on ART with evidence of virologic failure are also at high risk of transmitting HIV to their infants and require close follow-up. However, women stable on ART with a suppressed viral load before conception have a very low likelihood of HIV transmission and thus are strong candidates for multi-month ART dispensing, community-based distribution of ART, adherence clubs, community adherence support groups and longer intervals between clinical visits. A number of other factors should be considered when defining eligibility of mothers and infants for differentiated care, including location of services, viral load monitoring and duration on ART. To provide differentiated care that is client-centred and driven while encompassing a family-based approach, it will be critical to engage mothers, families and communities in models that will optimize client satisfaction, retention in care and quality of services. CONCLUSIONS: Differentiated care for mothers and infants represents an opportunity to provide client-centred care that reduces the burden on clients and health systems while improving the quality and uptake of services for families. However, with decreasing funding, stable HIV incidence, and aspirations for sustainability, it is critical to consider efficient, customized and cost-effective models of care for these populations as we aspire to eliminate mother-to-child transmission of HIV.

Increasing the volume, strengthening the quality, and proactively using data of human immunodeficiency virus (HIV) load testing are pivotal to limiting the threat of HIV drug resistance (HIVDR) accumulation,and allow for optimal case-based HIVDR surveillance. Triangulation of viral load (VL) and HIVDR testing data could be pursued to answer key questions and translate data and results for program and public policy. Identification of virologic failure and early management mitigates the greater risk of HIVDR. Routine VL monitoring and evaluation systems are necessary, and countries should consider reviewing system requirements, structural needs, and procedural and technical factors for the entire VL cascade, with special emphasis on post-test result use.

Landon Myer and colleagues discuss viral load monitoring for pregnant HIV-positive women and those breastfeeding; ART treatments can suppress viral load and are key to preventing transmission to the child.

INTRODUCTION: HIV-infected pregnant and breastfeeding adolescents are a particularly vulnerable group that require special attention and enhanced support to achieve optimal maternal and infant outcomes. The objective of this paper is to review published evidence about antenatal care (ANC) service delivery and outcomes for HIV-infected pregnant adolescents in low-income country settings, identify gaps in knowledge and programme services and highlight the way forward to improve clinical outcomes of this vulnerable group. DISCUSSION: Emerging data from programmes in sub-Saharan Africa highlight that HIV-infected pregnant adolescents have poorer prevention of mother-to-child HIV transmission (PMTCT) service outcomes, including lower PMTCT service uptake, compared to HIV-infected pregnant adults. In addition, the limited evidence available suggests that there may be higher rates of mother-to-child HIV transmission among infants of HIV-infected pregnant adolescents. CONCLUSIONS: While the reasons for the inferior outcomes among adolescents in ANC need to be further explored and addressed, there is sufficient evidence that immediate operational changes are needed to address the unique needs of this population. Such changes could include integration of adolescent-friendly services into PMTCT settings or targeting HIV-infected pregnant adolescents with enhanced retention and follow-up activities.

To meet the ambitious targets set by the Global Plan Towards the Elimination of New HIV Infections Among Children by 2015 and Keeping Their Mothers Alive (Global Plan), the initial 22 priority countries quickly developed innovative approaches for overcoming long-standing health systems challenges and providing HIV testing and treatment to pregnant and breastfeeding women and their infants. The Global Plan spurred programs for prevention of mother-to-child HIV transmission to integrate HIV-related care and treatment into broader maternal, newborn, and child health services; expand the effectiveness of the health workforce through task sharing; extend health services into communities; strengthen supply chain and commodity management systems; reduce diagnostic and laboratory hurdles; and strengthen strategic supervision and mentorship. The article reviews the ongoing challenges for prevention of mother-to-child HIV transmission programs as they continue to strive for elimination of vertical transmission of HIV infection in the post-Global Plan era. Although progress has been rapid, health systems still face important challenges, particularly follow-up and diagnosis of HIV-exposed infants, continuity of care, and the promotion of services that are respectful and client centered.

In 2015, the World Health Organization (WHO) recommended universal antiretroviral therapy (ART) for all people living with HIV (PLHIV) after two randomized controlled trials revealed lower rates of mortality and serious illnesses among PLHIV receiving immediate ART compared to those receiving deferred ART. Many countries in sub-Saharan Africa rapidly adopted this guidance and are implementing "test and start" programs.As this work begins, lessons learned from prevention of mother-to-child transmission (PMTCT) Option B+ programs can inform decisions for new universal HIV treatment programs. The Option B+ approach involved initiation of lifelong treatment for all HIV-infected pregnant and breastfeeding women. Since its inception in Malawi in 2011 and WHO endorsement in 2012, widespread scale-up of Option B+ PMTCT programs in most resource-limited countries has resulted in a dramatic increase in ART coverage for HIV-infected pregnant and breastfeeding women.Despite the overall success of the Option B+ universal lifelong treatment approach, program and operational research data highlight the need for additional focus on strategies to retain women in care. In this commentary, we highlight program considerations and lessons learned from Option B+ implementation experience in resource-limited countries which may help guide decisions and enhance the quality of general "test and start" programming.

Wildland fire fighters use many tools and equipment that produce noise levels that may be considered hazardous to hearing. This study evaluated 174 personal dosimetry measurements on 156 wildland fire fighters conducting various training and fire suppression tasks. Noise exposures often exceeded occupational exposure limits and suggest that wildland fire fighters may be at risk of developing noise-induced hearing loss, particularly those operating chainsaws, chippers, and masticators. The authors recommend a comprehensive approach to protecting these fire fighters that includes purchasing quieter equipment, noise and administrative controls, and enrolling these fire fighters into a hearing conservation program.

BACKGROUND: WHO recommends viral load (VL) as the preferred method for diagnosing antiretroviral therapy (ART) failure; however, operational challenges have hampered the implementation of VL monitoring in most resource-limited settings. This study evaluated the accuracy of dried blood spot (DBS) VL testing under field conditions as a practical alternative to plasma in determining virologic failure (VF). METHODS: From May to December 2013, paired plasma and DBS specimens were collected from 416 adults and 377 children on ART ≥6 months at 12 clinics in Kenya. DBS were prepared from venous blood (V-DBS) using disposable transfer pipettes, and from finger-prick capillary blood using microcapillary tube (M-DBS) and directly spotting (D-DBS). All samples were tested on Abbott m2000 platform; V-DBS was also tested on Roche-CAP/CTM Version 2.0 platform. VF results were compared at three DBS thresholds (≥1000, ≥3000 and ≥5000 copies/ml) and a constant plasma threshold of ≥1000 copies/ml. RESULTS: On Abbott platform, at ≥1000 copies/ml threshold, sensitivities, specificities, and Kappa values for VF determination were ≥88.1%, ≥93.1% and ≥0.82 respectively for all DBS methods and it had the lowest percentage of downward misclassification compared to higher thresholds. V-DBS performance on CAP/CTM had significantly poorer specificity at all thresholds (1000-33.0%, 3000-60.9%, 5000-77.0%). No significant differences were found between adults and children. CONCLUSION: VL results from V-DBS, M-DBS and D-DBS were comparable to plasma for determining VF using the Abbott platform but not with CAP/CTM. A 1000 copies/ml threshold was optimal and should be considered for VF determination using DBS in adults and children.

Pediatric human immunodeficiency virus (HIV) infection remains an important public health issue in resource-limited settings. In 2015, 1.4 million children aged <15 years were estimated to be living with HIV (including 170,000 infants born in 2015), with the vast majority living in sub-Saharan Africa. In 2014, 150,000 children died from HIV-related causes worldwide. Access to timely HIV diagnosis and treatment for HIV-infected infants reduces HIV-associated mortality, which is approximately 50% by age 2 years without treatment. Since 2011, the annual number of HIV-infected children has declined by 50%. Despite this gain, in 2014, only 42% of HIV-exposed infants received a diagnostic test for HIV, and in 2015, only 51% of children living with HIV received antiretroviral therapy (1). Access to services for early infant diagnosis of HIV (which includes access to testing for HIV-exposed infants and clinical diagnosis of HIV-infected infants) is critical for reducing HIV-associated mortality in children aged <15 years. Using data collected from seven countries supported by the U.S. President's Emergency Plan for AIDS Relief (PEPFAR), progress in the provision of HIV testing services for early infant diagnosis was assessed. During 2011-2015, the total number of HIV diagnostic tests performed among HIV-exposed infants within 6 weeks after birth (tests for early infant diagnosis of HIV), as recommended by the World Health Organization (WHO) increased in all seven countries (Cote d'Ivoire, the Democratic Republic of the Congo, Haiti, Malawi, South Africa, Uganda, and Zambia); however, in 2015, the rate of testing for early infant diagnosis among HIV-exposed infants was <50% in five countries. HIV positivity among those tested declined in all seven countries, with three countries (Cote d'Ivoire, the Democratic Republic of the Congo, and Uganda) reporting >50% decline. The most common challenges for access to testing for early infant diagnosis included difficulties in specimen transport, long turnaround time between specimen collection and receipt of results, and limitations in supply chain management. Further reductions in HIV mortality in children can be achieved through continued expansion and improvement of services for early infant diagnosis in PEPFAR-supported countries, including initiatives targeted to reach HIV-exposed infants, ensure access to programs for early infant diagnosis of HIV, and facilitate prompt linkage to treatment for children diagnosed with HIV infection.

The global commitment to reach the United Nations 90-90-90 targets will require a tremendous effort to almost double the number of HIV-infected individuals receiving antiretroviral treatment (ART), from 15.8 to 29.9 million, in the next 4 years [1]. In sub-Saharan Africa alone, ART initiation for an additional 6.2 million persons will be needed to reach this target. Given the infrastructure constraints and healthcare worker shortages in many resource-limited settings, there is increasing recognition that traditional facility-based models of clinician-led HIV service delivery will not be feasible with the increase in patient volume. In response, multiple proposed alternative service delivery models have been developed that center on transitioning at least some aspects of care out of health facilities into the community to decongest clinics and maximize the use of limited healthcare worker resources [2]. | Several commonly employed service delivery modifications have documented success in improving patient outcomes. One of the most common focuses on multimonth prescribing in which pharmacies dispense more than a month's supply of ART, requiring fewer patient visits to collect medications [2]. Another employs alternative ART delivery points; for example, HIV-infected patients can collect their ART at a community pharmacy/drug delivery site or have ART delivered to their homes by a cadre of lay workers [3]. A third model reduces the number of required follow-up visits for certain patients, most often those considered ‘stable’ by criteria such as time on ART and/or viral load suppression. These patients are seen at the facility by medical staff only once or twice per year [4]. Other models employ community adherence clubs, where groups of HIV-infected individuals receive all of their medication and care in the community on a particular day [5]. Finally, community ART groups rely on the member of the group to collect monthly antiretrovirals (ARVs) for all members while visiting the health facility for their yearly/biyearly visit [6]. This list is not exhaustive, and new strategies ideally suited for specific populations are continuing to be implemented. However, one commonality among most alternative models of ART service delivery is that children have almost uniformly been excluded.

Persons who died of Ebola virus disease at home in rural communities in Liberia and Guinea resulted in more secondary infections than persons admitted to Ebola treatment units. Intensified monitoring of contacts of persons who died of this disease in the community is an evidence-based approach to reduce virus transmission in rural communities.

To achieve global targets for universal treatment set forth by the Joint United Nations Programme on human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) (UNAIDS), viral load monitoring for HIV-infected persons receiving antiretroviral therapy (ART) must become the standard of care in low- and middle-income countries (LMIC) (1). CDC and other U.S. government agencies, as part of the President's Emergency Plan for AIDS Relief, are supporting multiple countries in sub-Saharan Africa to change from the use of CD4 cell counts for monitoring of clinical response to ART to the use of viral load monitoring, which is the standard of care in developed countries. Viral load monitoring is the preferred method for immunologic monitoring because it enables earlier and more accurate detection of treatment failure before immunologic decline. This report highlights the initial successes and challenges of viral load monitoring in seven countries that have chosen to scale up viral load testing as a national monitoring strategy for patients on ART in response to World Health Organization (WHO) recommendations. Countries initiating viral load scale-up in 2014 observed increases in coverage after scale-up, and countries initiating in 2015 are anticipating similar trends. However, in six of the seven countries, viral load testing coverage in 2015 remained below target levels. Inefficient specimen transport, need for training, delays in procurement and distribution, and limited financial resources to support scale-up hindered progress. Country commitment and effective partnerships are essential to address the financial, operational, technical, and policy challenges of the rising demand for viral load monitoring.

We measured the reproduction number before and after interventions were implemented to reduce Ebola transmission in 9 outbreaks in Liberia during 2014. We evaluated risk factors for secondary cases and the association between patient admission to an Ebola treatment unit (ETU) and survival. The reproduction number declined 94% from 1.7 (95% CI 1.1-2.6) to 0.1 (95% CI 0.02-0.6) after interventions began. The risk for secondary infections was 90% lower for patients admitted to an ETU (risk ratio 0.1, 95% CI 0.04-0.3) than for those who died in the community. The case-fatality rate was 68% (95% CI 60-74), and ETU admission was associated with a 50% reduction in death (hazard ratio 0.5, 95% CI 0.4-0.8). Isolation and treatment of Ebola patients had the dual benefit of interrupting community transmission and improving survival.

As late as September 14, 2014, Liberia's Gbarpolu County had reported zero cases of Ebola virus disease (Ebola). On October 25, the Bong County Health Team, a local health department in the Liberian Ministry of Health and Social Welfare (MOHSW), received confirmation of Ebola in a man who had recently left Geleyansiesu, a remote village of approximately 800 residents, after his wife and daughter had died of illnesses consistent with Ebola. MOHSW requested assistance from CDC, the World Health Organization, and other international partners to investigate and confirm the outbreak in Geleyansiesu and begin interventions to interrupt transmission. A total of 22 cases were identified, of which 18 (82%) were laboratory confirmed by real-time polymerase chain reaction. There were 16 deaths (case-fatality rate = 73%). Without road access to or direct telecommunications with the village, interventions had to be tailored to the local context. Public health interventions included 1) education of the community about Ebola, transmission of the virus, signs and symptoms, the importance of isolating ill patients from family members, and the potential benefits of early diagnosis and treatment; 2) establishment of mechanisms to alert health authorities of possibly infected persons leaving the village to facilitate safe transport to the closest Ebola treatment unit (ETU); 3) case investigation, contact tracing, and monitoring of contacts; 4) training in hygienic burial of dead bodies; 5) active case finding and diagnosis; and 6) isolation and limited no-touch treatment in the village of patients unwilling or unable to seek care at an ETU. The findings of this investigation could inform interventions aimed at controlling focal outbreaks in difficult-to-reach communities, which has been identified as an important component of the effort to eliminate Ebola from Liberia.

West Africa is experiencing its first epidemic of Ebola virus disease (Ebola). As of February 9, Liberia has reported 8,864 Ebola cases, of which 3,147 were laboratory-confirmed. Beginning in August 2014, the Liberia Ministry of Health and Social Welfare (MOHSW), supported by CDC, the World Health Organization (WHO), and others, began systematically investigating and responding to Ebola outbreaks in remote areas. Because many of these areas lacked mobile telephone service, easy road access, and basic infrastructure, flexible and targeted interventions often were required. Development of a national strategy for the Rapid Isolation and Treatment of Ebola (RITE) began in early October. The strategy focuses on enhancing capacity of county health teams (CHT) to investigate outbreaks in remote areas and lead tailored responses through effective and efficient coordination of technical and operational assistance from the MOHSW central level and international partners. To measure improvements in response indicators and outcomes over time, data from investigations of 12 of 15 outbreaks in remote areas with illness onset dates of index cases during July 16-November 20, 2014, were analyzed. The times to initial outbreak alerts and durations of the outbreaks declined over that period while the proportions of patients who were isolated and treated increased. At the same time, the case-fatality rate in each outbreak declined. Implementation of strategies, such as RITE, to rapidly respond to rural outbreaks of Ebola through coordinated and tailored responses can successfullyreduce transmission and improve outcomes.

Beta-hemolytic group C and G streptococci cause a considerable invasive disease burden and sometimes cause disease outbreaks. Little is known about the critical epidemiologic parameter of genetic relatedness between isolates. We determined the emm types of 334 Streptococcus dysgalactiae subsp. equisimilis isolates, and attempted emm typing of 5 Streptococcus canis isolates from a recent population-based surveillance for invasive isolates. Thirty-four emm types were observed, including one from S. canis. We formulated multilocus sequence typing (MLST) primers with six of the seven loci corresponding to the Streptococcus pyogenes MLST scheme. We performed MLST with 65 of the 334 surveillance isolates (61 S. dysgalactiae subsp. equisimilis isolates, 4 S. canis isolates) to represent each emm type identified, including 2 to 3 isolates for each of the 25 redundantly represented emm types. Forty-one MLST sequence types (STs) were observed. Isolates within 16 redundantly represented S. dysgalactiae subsp. equisimilis emm types shared identical or nearly identical STs, demonstrating concordance between the emm type and genetic relatedness. However, seven STs were each represented by two to four different emm types, and 7 of the 10 S. dysgalactiae subsp. equisimilis eBURST groups represented up to six different emm types. Thus, S. dysgalactiae subsp. equisimilis isolates were similar to S. pyogenes isolates, in that strains of the same emm type were often highly related, but they differed from S. pyogenes, in that S. dysgalactiae subsp. equisimilis strains with identical or closely similar STs often exhibited multiple unrelated emm types. The phylogenetic relationships between S. dysgalactiae subsp. equisimilis and S. pyogenes alleles revealed a history of interspecies recombination, with either species often serving as genetic donors. The four S. canis isolates shared highly homologous alleles but were unrelated clones without evidence of past recombination with S. dysgalactiae subsp. equisimilis or S. pyogenes.