https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(09)60829-1.pdf

Human African trypanosomiasis

Trypanosoma evansi, the agent of “surra,” is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies). It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin America. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles, and elephants. It found a new large range of wild and domestic hosts in Latin America, including reservoirs (capybaras) and biological vectors (vampire bats). Surra is a major disease in camels, equines, and dogs, in which it can often be fatal in the absence of treatment, and exhibits nonspecific clinical signs (anaemia, loss of weight, abortion, and death), which are variable from one host and one place to another; however, its immunosuppressive effects interfering with intercurrent diseases or vaccination campaigns might be its most significant and questionable aspect.

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Trypanosoma evansi and Surra: A Review and Perspectives on Origin, History, Distribution, Taxonomy, Morphology, Hosts, and Pathogenic Effects

This review discusses the challenges of chemotherapy for human African trypanosomiasis (HAT). The few drugs registered for use against the disease are unsatisfactory for a number of reasons. HAT has two stages. In stage 1 the parasites proliferate in the haemolymphatic system. In stage 2 they invade the central nervous system and brain provoking progressive neurological dysfunction leading to symptoms that include the disrupted sleep wake patterns that give HAT its more common name of sleeping sickness. Targeting drugs to the central nervous system offers many challenges. However, it is the cost of drug development for diseases like HAT, that afflict exclusively people of the world's poorest populations, that has been the principal barrier to new drug development and has led to them becoming neglected. Here we review drugs currently registered for HAT, and also discuss the few compounds progressing through clinical trials. Finally we report on new initiatives that might allow progress to be made in developing new and satisfactory drugs for this terrible disease.

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Human African trypanosomiasis: pharmacological re-engagement with a neglected disease

Pathogenic animal trypanosomes affecting livestock have represented a major constraint to agricultural development in Africa for centuries, and their negative economic impact is increasing in South America and Asia. Chemotherapy and chemoprophylaxis represent the main means of control. However, research into new trypanocides has remained inadequate for decades, leading to a situation where the few compounds available are losing efficacy due to the emergence of drug-resistant parasites. In this review, we provide a comprehensive overview of the current options available for the treatment and prophylaxis of the animal trypanosomiases, with a special focus on the problem of resistance. The key issues surrounding the main economically important animal trypanosome species and the diseases they cause are also presented. As new investment becomes available to develop improved tools to control the animal trypanosomiases, we stress that efforts should be directed towards a better understanding of the biology of the relevant parasite species and strains, to identify new drug targets and interrogate resistance mechanisms.

/pdf/the-animal-trypanosomiases-and-their-chemotherapy-a-review-ib7muhfhhz.pdf

The animal trypanosomiases and their chemotherapy: a review.

This paper reviews the transmission modes of Trypanosoma evansi. Its worldwide distribution is attributed to mechanical transmission. While the role of tabanids is clear, we raise questions on the relative role of Haematobia sp. and the possible role of Stomoxys sp. in delayed transmission. A review of the available trypanocidal drugs and their efficacy in various host species is useful for understanding how they interact in disease epidemiology, which is complex. Although there are similarities with other mechanically transmitted trypanosomes, T. evansi has a more complex epidemiology due to the diversity of its hosts and vectors. The impact of clinical and subclinical disease is difficult to establish. A model was developed for buffaloes in the Philippines, which could be transferred to other places and livestock systems. Since Trypanosoma evansi was reported in humans, further research is required to investigate its zoonotic potential. Surra remains a potentially emerging disease that is a threat to Australia, Spain, and France. A number of questions about the disease have yet to be resolved. This brief review of the basic knowledge of T. evansi suggests that there is renewed interest in the parasite, which is spreading and has a major economic impact.

/pdf/trypanosoma-evansi-and-surra-a-review-and-perspectives-on-1zz0rj7pjz.pdf

Trypanosoma evansi and Surra: A Review and Perspectives on Transmission, Epidemiology and Control, Impact, and Zoonotic Aspects

We report an Indian farmer who had fluctuating trypanosome parasitemia associated with febrile episodes for five months. Morphologic examination of the parasites indicated the presence of large numbers of trypanosomes belonging to the species Trypanosoma evansi, which is normally a causative agent of animal trypanosomiasis known as surra. Basic clinical and biologic examinations are described, using several assays, including parasitologic, serologic, and molecular biologic tests, all of which confirmed the infecting species as T. evansi. Analysis of cerebrospinal fluid indicated no invasion of the central nervous system (CNS) by trypanosomes. Suramin, a drug used exclusively for treatment of early-stage human African trypanosomiasis with no CNS involvement, effected apparent cure in the patient. This is the first case reported of human infection due to Trypanosoma evansi, which was probably caused by transmission of blood from an infected animal.

Human trypanosomiasis caused by trypanosoma evansi in india: the first case report

After discovery of the first recorded case of human infection with Trypanosoma evansi, serologic screening of 1,806 persons from the village of origin of the patient in India was performed using the card agglutination test for trypanosomiasis and T. evansi. A total of 410 (22.7%) people were positive by whole blood, but only 81 were confirmed positive by serum. However, no trypanosomes were detected in the blood of 60 people who were positive at a high serum dilution. The results probably indicate frequent exposure of the human population to T. evansi in the study area, which suggests frequent vector transmission of parasites to humans. Although T. evansi is not infective for humans, a follow-up of seropositive persons is required to observe the evolution of human infection with this parasite.

Human trypanosomiasis caused by trypanosoma evansi in a village in india: preliminary serologic survey of the local population

Dear Editor, Anogenital warts, especially on the penile region are rare in children. Treatment can be challenging due to their recurrent nature and destructive property of most treatment modalities. Here, we report a case of florid anogenital warts in a 7-month boy with dramatic response to imiquimod 5% cream. A 7-month-old boy presented with cauliflower-like growth on the penis, scrotum and perianal region for last 3.5 months. The baby was born by a term normal vaginal delivery at a hospital. The child was circumcised in a non-hospital setting 2 weeks before the onset of the lesions. No history of sexual abuse could be elicited. On examination, multiple skin colored verrucous papules coalescing to form plaques were seen on the glans penis, penile shaft and scrotum (Figures 1A, B). Single verrucous papule was prsent in the perianal region. The child's parents did not have any evidence of cutaneous or anogenital warts. Both parents' and child's venereal disease research laboratory (VDRL) and human immunodeficiency virus (HIV) serologies were negative. Histopathology from penile lesion showed basket weave hyperkeratosis, papillomatosis, prominent granular layer, koilocytes in the stratum granulosum and dilated blood vessels in the papillary dermis (Figures S1A and S1B). Tissue polymerase chain reaction (PCR) was positive for human papillomavirus (HPV) 11 (Figure S1C). After explaining the possibility of spontaneous resolution of the lesions and discussing the treatment options available, the parents insisted on active intervention. The child was started on imiquimod 5% cream to be applied once at bedtime on alternate days for 6 weeks. The parents could not bring the child for follow-up due to the ongoing COVID-19 pandemic. The lesions cleared completely after 6 weeks of imiquimod, with no side effects, according to the image provided by the parents (Figure 1C). There was no recurrence at 8 months of follow-up, as per telephonic consultation. Extensive anogenital warts are uncommon in children. Most of these are asymptomatic, but can be associated with ulceration, pain and bleeding, making treatment necessary. Large anogenital warts in children can be challenging to manage, with no specific treatment guidelines. Sexual abuse must be considered, especially if the child is more than 3 years of age. A study found that male circumcision decreased the acquisition and increased the clearance of high-risk HPV in adults. However, in our case the lesions started after circumcision, which may be attributed to the non-hospital setting in which it was done. Most modalities for the treatment of anogenital warts are destructive, with limited acceptability in children. Topical medications such as imiquimod 5%, podofilox 0.5%, sinecatechins ointment 15% and diphenylcyclopropenone have been used in children with encouraging results. Imiquimod is an immune stimulator that acts on the Toll-like receptors (TLRs)7 and 8 and enhances production of interferons, tumor necrosis factor-α and interleukins1, 6 and 8.

Florid anogenital warts in a 7‐month‐old boy with rapid response to imiquimod

Background: According to the World Health Organization, 6 million cases of syphilis occur every year. Serological tests for syphilis form the mainstay of diagnosis for syphilis. We evaluated the performance of point-of-care test (POCT) against other specific treponemal test for confirming the diagnosis of syphilis. Materials and Methods: Does performance and operational superiority of POCT make it the investigation of choice in confirming syphilis? Retrospectively, data were analyzed of 599 serum samples from Apex Regional sexually transmitted disease centre, Safdarjung Hospital, New Delhi, received for testing by syphilis treponemal assays (both nontreponemal reactive and nonreactive). These samples underwent treponemal testing for syphilis by the Treponema pallidum hemagglutination (TPHA), fluorescent treponemal antibody absorption test (FTA-ABS), and POCT. Performance characteristics (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], and diagnostic accuracy), and operational characteristics of POCT and TPHA were evaluated against the gold standard FTA-ABS. Results: A total of 599 samples were evaluated, of which 61.76% were positive by FTA-ABS. On analysis, the sensitivity was 91.08% and 91.89%, specificity was 89.08% and 87.34%, PPV was 93.09% and 92.14%, NPV was 86.08% and 86.96%, and diagnostic accuracy was 90.32% and 90.15% for POCT and TPHA, respectively. The lower cost, shorter turnaround time, lesser infrastructure and workforce need, and easy availability make the POCT operationally superior to TPHA. Conclusion: Owing to its operational superiority and higher specificity POCT can replace TPHA for confirming the diagnosis of Syphilis. POCT are affordable, equipment free, have room temperature storage, and yield result within 15 minutes, enabling same day testing and treatment. It can be used in a resource limited setting, for community setup or even self-testing.

Does performance and operational superiority of point-of-care test make it the investigation of choice in confirming syphilis?

Substantial increase in the outbreaks of sexually transmitted infections (STIs) and associated mortalities have raised international concerns. Concurrent with the escalation of established STIs, developing epidemics and outbreaks of newly emerging sexually transmissible pathogens pose serious problems for people and added burden and challenges for public health practitioners and researchers. Importantly, most of the emerging STIs are frequently found among vulnerable groups, such as men having sex with men and human immunodeficiency virus patients, which may result in large outbreaks in the near future. Furthermore, enhanced spread of antimicrobial resistance among these pathogens ever more limits treatment options for STIs. Thus, it is the optimal time to consider whether an infectious agent is sexually transmissible and develop treatment protocol for handling new STIs with pandemic potential. In this review, we explore emerging STIs, their current epidemiological status, and future perspective.

Aradhana Bhargava

Papers

Human trypanosomiasis caused by trypanosoma evansi in india: the first case report

Human trypanosomiasis caused by trypanosoma evansi in a village in india: preliminary serologic survey of the local population

Florid anogenital warts in a 7‐month‐old boy with rapid response to imiquimod

Does performance and operational superiority of point-of-care test make it the investigation of choice in confirming syphilis?

Emerging and re-emerging sexually transmitted diseases: A review of epidemiological evidences