Transmission of viable Haemophilus ducreyi by Musca domestica.

Haemophilus ducreyi was historically known as the causative agent of chancroid, a sexually-transmitted disease causing painful genital ulcers endemic in many low/middle-income nations. In recent years the species has been implicated as the causative agent of nongenital cutaneous ulcers affecting children of the South Pacific Islands and West African countries. Much is still unknown about the mechanism of H. ducreyi transmission in these areas, and recent studies have identified local insect species, namely flies, as potential transmission vectors. H. ducreyi DNA has been detected on the surface and in homogenates of fly species sampled from Lihir Island, Papua New Guinea. The current study develops a model system using Musca domestica, the common house fly, as a model organism to demonstrate proof of concept that flies are a potential vector for the transmission of viable H. ducreyi. Utilizing a green fluorescent protein (GFP)-tagged strain of H. ducreyi and three separate exposure methods, we detected the transmission of viable H. ducreyi by 86.11% ± 22.53% of flies sampled. Additionally, the duration of H. ducreyi viability was found to be directly related to the bacterial concentration, and transmission of H. ducreyi was largely undetectable within one hour of initial exposure. Push testing, Gram staining, and PCR were used to confirm the identity and presence of GFP colonies as H. ducreyi. This study confirms that flies are capable of mechanically transmitting viable H. ducreyi, illuminating the importance of investigating insects as vectors of cutaneous ulcerative diseases.

Despite Being "Known, Highly Promiscuous and Active": Presumed Heterosexuality in the USPHS's STD Inoculation Study, 1946-48.

The Sexually Transmitted Disease Inoculation Study of the United States Public Health Service (USPHS) was a short-term deliberate exposure experiment into the prevention of venereal diseases. Between 1946 and 1948, over 1,300 Guatemalan prisoners, psychiatric patients, soldiers, and sex workers were exposed to syphilis, gonorrhoea, and chancroid. USPHS researchers initially proposed hiring sex workers to "naturally" transmit venereal diseases to male subjects who would then be given various prophylaxes. The researchers were interested in studying the effectiveness of new preventative measures. In other words, the USPHS study was designed to transmit venereal diseases heterosexually from an "infected" female body to the men who, it was assumed, were sexually isolated subjects. However, the researchers did record instances of male-to-male disease transmission among their subject populations, instances that challenged the presumption of heterosexuality on which the study was based.

[Sexually Transmitted Infections in the Tropics]. / Sexuell übertragbare Infektionen in den Tropen.

Sexually transmitted infections (STI) are common all over the world and the incidence of chlamydia, gonorrhea, syphilis and trichomoniasis alone is estimated at 500 million/year. Of these infections 75% occur in tropical countries in Latin America, sub-Saharan Africa and South as well as Southeast Asia. The bacterial infections chancroid, lymphogranuloma venereum (LGV) and granuloma inguinale (GI, Donovanosis) are termed tropical STI. They occur mainly in tropical countries, i. e. regions situated between the equator and the northern and southern 23.5° latitudes, regions which are characterized by hot humid climates as well as poverty and underdevelopment. These three diseases are primarily associated with ulcerations of the skin, thus their presence represents an increased risk for transmission of HIV and other STI. As with all STI, to minimize the risk of tropical infections it is essential to avoid hazardous sexual practices and to use condoms.

Sexually Transmitted Infections in Melbourne, Australia from 1918 to 2016: nearly a century of data.

INTRODUCTION: Our aim was to describe trends in the number of bacterial sexually transmitted infections (STIs) diagnosed at Melbourne's sexual health clinic over a century. METHODS: A retrospective analysis of STI diagnoses (gonorrhoea, infectious syphilis and chancroid) among individuals attending Melbourne's sexual health service over 99 years between 1918 and 2016. RESULTS: Substantial increases in STI rates coincided with World War II, the 'Sexual Revolution of the 1960s and 1970s', and the last 10 years. Substantial declines coincided with the advent of antibiotics and the HIV/AIDS pandemic. There were also key differences between STIs. Chancroid virtually disappeared after 1950. Syphilis fell to very low levels in women after about 1950 and has only rebounded in men. The declines in gonorrhoea were less marked. A substantial peak in gonorrhoea occurred in women in the early 1970s and rates are currently rising in women, albeit much less than in men. CONCLUSIONS: Both antibiotics and changing sexual behaviour have had a powerful effect on STI rates. These data suggest gonorrhoea is more difficult to control than syphilis or chancroid. Indeed, the past rates suggest substantial endemic gonorrhoea transmission in heterosexuals occurred in the third quarter of last century before the appearance of the HIV pandemic. Worryingly, there is a suggestion that endemic heterosexual gonorrhoea may be returning. The data also suggest that future control of gonorrhoea and syphilis in men who have sex with men is going to be challenging.

Chancroid transmission dynamics: a mathematical modeling approach.

Mathematical models have long been used to better understand disease transmission dynamics and how to effectively control them. Here, a chancroid infection model is presented and analyzed. The disease-free equilibrium is shown to be globally asymptotically stable when the reproduction number is less than unity. High levels of treatment are shown to reduce the reproduction number suggesting that treatment has the potential to control chancroid infections in any given community. This result is also supported by numerical simulations which show a decline in chancroid cases whenever the reproduction number is less than unity.

On the evolution of the sexually transmitted bacteria Haemophilus ducreyi and Klebsiella granulomatis.

Haemophilus ducreyi and Klebsiella (Calymmatobacterium) granulomatis are sexually transmitted bacteria that cause characteristic, persisting ulceration on external genitals called chancroid and granuloma inguinale, respectively. Those ulcers are endemic in developing countries or exist, as does granuloma inguinale, only in some geographic "hot spots."H. ducreyi is placed in the genus Haemophilus (family Pasteurellacae); however, this phylogenetic position is not obvious. The multiple ways in which the bacterium may be adapted to its econiche through specialized nutrient acquisitions; defenses against the immune system; and virulence factors that increase attachment, fitness, and persistence within genital tissue are discussed below. The analysis of K. granulomatis phylogeny demonstrated a high degree of identity with other Klebsiella species, and the name K. granulomatis comb. nov. was proposed. Because of the difficulty in growing this bacterium on artificial media, its characteristics have not been sufficiently defined. More studies are needed to understand bacterial genetics related to the pathogenesis and evolution of K. granulomatis.

[Import and local transmission of Haemophilus ducreyi]. / Import og lokal transmission af Haemophilus ducreyi.

Chancroid is a sexually transmitted disease characterized by painful ulcers with a soft margin, necrotic base and purulent exudate. Previously, only sporadic, imported cases have been reported in Denmark. The bacterium is difficult to culture and novel polymerase chain reaction (PCR)-based methods for direct demonstration of bacterial DNA have facilitated rapid verification of the clinical diagnosis. We report two cases which demonstrate import and subsequent local transmission in Denmark. In both cases, the clinical diagnosis was rapidly verified by a combined PCR testing for multiple causes of venereal ulcers.

Experimental infection of human volunteers with Haemophilus ducreyi: fifteen years of clinical data and experience.

Haemophilus ducreyi causes chancroid, which facilitates transmission of human immunodeficiency virus type 1. To better understand the biology of H. ducreyi, we developed a human inoculation model. In the present article, we describe clinical outcomes for 267 volunteers who were infected with H. ducreyi. There was a relationship between papule formation and estimated delivered dose. The outcome (either pustule formation or resolution) of infected sites for a given subject was not independent; the most important determinants of pustule formation were sex and host effects. When 41 subjects were infected a second time, their outcomes segregated toward their initial outcome, confirming the host effect. Subjects with pustules developed local symptoms that required withdrawal from the study after a mean of 8.6 days. There were 191 volunteers who had tissue biopsy performed, 173 of whom were available for follow-up analysis; 28 (16.2%) of these developed hypertrophic scars, but the model was otherwise safe. Mutant-parent trials confirmed key features in H. ducreyi pathogenesis, and the model has provided an opportunity to study differential human susceptibility to a bacterial infection.

[Chancroid]. / Ulcus molle.

Chancroid is caused by the bacterium Haemophilus ducreyi. It is a sexually transmitted disease causing a soft chancre with a necrotic base and purulent exudate. The incidence of this illness is very low in Denmark and is probably underestimated. The bacterium is very fragile in transport, and culture is often negative. The chance of demonstrating the bacterium is greatly enhanced by the use of molecular techniques. In this case, we report on a specific PCR test for H. ducreyi that was used to establish the diagnosis in a 40-year-old male.

[Diagnosis of major sexually transmitted infections in the doctor's office: bacterial infections]. / Diagnostik sexuell übertragener Krankheiten: Bakterielle Infektionen. Kennen Sie die "Kieler Masern"?

Bacterial infections that can be transmitted by sexual contact are usually caused by the following organisms: Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum and Klebsiella granulomatis. These pathogens can be detected with the aid of specific nutrient media, stained microscopic sections and serological and molecular biological methods.

Eradicating chancroid.

Genital ulcers are important cofactors of HIV transmission in the countries most severely affected by HIV/AIDS. Chancroid is a common cause of genital ulcer in all 18 countries where adult HIV prevalence surpasses 8% and is rare in countries with low-level HIV epidemics. Haemophilus ducreyi, the causative organism of chancroid, is biologically vulnerable and occupies a precarious epidemiological niche. Both simple, topical hygiene and male circumcision greatly reduce risk of infection and several classes of antibiotics--some of which can be administered in single-dose treatment regimens--provide rapid cure. H. ducreyi depends on sexual networks with high rates of partner change for its survival, thriving in environments characterized by male mobility and intensive commercial sex activity. Elimination of H. ducreyi infection from vulnerable groups results in disappearance of chancroid from the larger community. Once endemic in Europe and North America, chancroid began a steady decline early in the twentieth century, well before the discovery of antibiotics. Social changes--resulting in changing patterns of commercial sex--probably disrupted the conditions needed to sustain chancroid as an endemic disease. Sporadic outbreaks are now easily controlled when effective curative and preventive services are made available to sex workers and their clients. More recently, chancroid prevalence has declined markedly in countries such as the Philippines. Senegal, and Thailand, a development that may contribute to stabilization of the HIV epidemics in these countries. Eradication of chancroid is a feasible public health objective. Protecting sex workers and their clients from exposure to sexually transmitted diseases (STDs) and improving curative services for STDs are among the proven strategies that could be employed.

Sexually transmitted diseases in children in developing countries.

PIP: The populations of developing countries have younger age structures than the populations of more developed, Western countries. That is, children, adolescents, and youth constitute a far greater proportion of the populations of developing countries than in developed countries. These young people experiment with sex and sexual intercourse or have coitus on a regular basis depending upon their individual personalities and circumstances. The prevalence of sexually transmitted diseases (STD) among younger age groups in developing countries is not well documented. It may, however, be inferred on the basis of reported experience of STD in surveys of adolescents and young adults that many children are infected with STDs. Some young people have sex consensually, some are coaxed into it, and others are coerced. On the one hand, young children have been thought to contract STD by sitting on the laps of infected, scantily-clad adults where such limited attire is the norm. Close contact between youngsters such as communal sleeping, for example, could then facilitate the spread of the STD among children. Sex, consensual or otherwise, is not involved in such infection and transmission beyond the index adult. On the other hand, however, many children and adolescents are forced to have sexual relations and/or intercourse either directly against their will or as a result of the primal need to ensure their individual survival. For example, there are an estimated 100-200 million street children worldwide; many have little alternative but to sell sex to survive. When having sex, they may not use condoms because they are unaware of the STD risk they face, they have no access to free condoms, clients/employers/peers prevent them from using condoms, or due to a myriad of other reasons. Struggling to survive, many such kids place condom use very low on their list of priorities. Children and adolescents can also become infected and transmit STDs to others by engaging in sexual intercourse under more narrowly-defined cultural norms. For example, the belief exists that a male with urethritis can be cured by sexual intercourse with a virgin or prepubertal girl. Elsewhere, it is normal practice for an adult male, typically a boy's uncle, to have anal insertive sexual intercourse with the boy on a regular basis over the period of a couple years to facilitate his transition into manhood. People in young age groups around the world have sex for a range of reasons under a variety of conditions. Measures are needed to ensure that they have the means to prevent infection with STDs and control that infection, if possible, once acquired. Sections discuss vulvovaginitis, donovanosis, chancroid, and venereal and nonvenereal treponematosis, as well as prevention and future research.^ieng

A primate model for chancroid.

Adult pigtailed macaques (Macaca nemestrina) were evaluated for their usefulness as a primate model for chancroid. To initiate infection, 10(7)-10(8) cfu of Haemophilus ducreyi were inoculated into the foreskins of 5 adult males and into the vaginal labia of 4 adult females. Lesions developed in the male macaques that were similar in appearance, histopathologic changes, and progression to those of human disease, including the development of ulcers 6-12 days after infection. In addition, H. ducreyi could be recovered from the lesions up to 20 days after inoculation, humoral antibodies were induced beginning 1 week after inoculation, and inguinal lymphadenopathy was noted in 4 of the 5 males. None of the 4 female macaques inoculated with the same preparation of live H. ducreyi developed comparable lesions. Thus, experimental chancroid in adult male macaques closely resembles human disease and should be useful for future studies of the pathogenesis of chancroid.

Recent changes in the epidemiology of genital ulcer disease in the United States. The crack cocaine connection.

The incidence of syphilis and chancroid began to increase in the United States among heterosexuals in the mid-1980s, with most cases reported among minorities living in Eastern cities and in the South. A number of studies have established a link between increasing syphilis incidence rates and cocaine use, specifically the smoked form of the drug, which is known as "crack." A similar link was hypothesized for chancroid, but supporting data became available only recently. In New Orleans, we showed that Haemophilus ducreyi infection in male patients was strongly associated with crack cocaine use. However, our studies also demonstrated that drug use by the patient actually was a marker for a more important risk factor: sexual exposure to a cocaine-using woman. Thus, although the details of the relationships among crack, sexual behavior, and the size and nature of core transmitter groups are not known, it is clear that crack cocaine abuse is the driving force behind the recent syphilis and chancroid epidemics in the United States. Although it is not possible to predict the effects of these events on human immunodeficiency virus (HIV) transmission, the potential for significant synergism between them exists. New approaches to HIV surveillance should be developed taking this possibility into account. During the last 3 to 4 years, incidence rates of syphilis and chancroid have fallen in the United States, despite continued problems throughout the country with crack cocaine abuse. However, our studies and those of others have shown how difficult it is to recognize chancroid clinically, suggesting that the disease may be grossly underreported.(ABSTRACT TRUNCATED AT 250 WORDS)

[Sexually transmissible diseases following travel in tropical countries]. / Sexuell übertragbare Krankheiten nach Reisen in tropische Länder.

Travel to tropical countries is an important factor in the spread of sexually transmitted diseases. In spite of intensive anti-AIDS campaigns, some 30% of Swiss tourists have casual sexual contacts abroad. The prevalence of sexually transmitted diseases is higher in tropical countries than in western industrialized countries. More than 25% of cases of gonorrhea treated in Switzerland from 1989-1991 were imported from abroad. The penicillin producing Neisseria gonorrhoeae strains (PPNG) isolated in Switzerland from 1989-1991 are mainly imported from abroad (60%). The typical "imported sexually transmitted diseases" in Switzerland are chancroid, lymphogranuloma venereum and donovanosis. The clinical manifestations, laboratory and special examinations, and treatment of these diseases are described. The most frequent sexually transmitted disease from the so-called "imported tropical STD's" is chancroid. Chancroid is also a major risk factor for HIV infection.

Rapid control of a chancroid outbreak: implications for Canada.

From June to November 1987 an outbreak of chancroid occurred in Winnipeg, the first in more than 10 years; 14 people (9 men, 5 women) were involved. Nine of the cases were confirmed through culture. A control strategy was implemented in November 1987 that included presumptive treatment of genital ulcer disease with single-dose antimicrobial therapy, intensive tracing of contacts and treatment of asymptomatic sexual contacts. The origin of the outbreak was not determined, and an epidemiologic link between all the patients could not be demonstrated. The isolates were found to contain the same plasmid; this suggested that a single clone of Haemophilus ducreyi was responsible for the outbreak.

Imported pedal chancroid: case report.

A man aged 22 who had returned from the Fiji Islands to Denmark had chancroid on the left foot, but no history or sign of primary genital infection. The pedal location only is an unusual presentation of the disease, which was diagnosed only microbiologically. Chronic tropical ulcers therefore demand special microbiological attention.