Amphotericin B Deoxycholate Treatment of Post-Kala-Azar Dermal Leishmaniasis in India.

Post-kala-azar dermal leishmaniasis (PKDL) is widely prevalent in the endemic regions of India, but its treatment remains unsatisfactory. The WHO recommends a 12-week treatment with oral miltefosine, but its ocular toxicities are a serious concern. The late 1980s and early 1990s saw the use of sodium stibogluconate and amphotericin B (AmB) for a brief period. Both drugs had frequent adverse events and were expensive, and the duration of treatments was unacceptably long. This retrospective study evaluated, analyzed, and reported the outcomes of PKDL patients treated with a shorter course of AmB, the most effective antileishmanial drug. The hospital records of PKDL patients treated with AmB by 30 alternate-day infusions over 60 days (instead of conventional 60-80 infusions over 100-120 days) between September 2010 and August 2016 were reviewed. Only patients with confirmed parasitological diagnosis were included. Their records were studied for treatment-related adverse events, end-of-treatment parasitological status, and 12-month follow-up results. One hundred two patients were eligible for this study between September 2010 and August 2016. After therapy, 92/102 (90.2%) patients improved; 3 (2.9%) had to cease treatment owing to severe adverse effects, and one died of severe diarrhea unrelated to AmB. Six (5.9%) patients withdrew consent before the treatment was complete. At the 12-month evaluation, 89/102 (87.3%) patients attained a final cure. A 30-infusion regimen of AmB remains highly effective in PKDL. Without a shorter, safer, and more economical regimen for the treatment of PKDL, it should be used until a better regimen is available.

Phenotypic and functional characteristics of monocyte subsets in the blood and bone marrow of Indian subjects with Visceral Leishmaniasis.

Visceral leishmaniasis (VL) is a potentially fatal parasitic infection caused by Leishmania donovani in India. L. donovani is an obligate intracellular protozoan residing mostly in macrophages of the reticuloendothelial system throughout chronic infection. Monocytic phagocytes are critical in the pathogenesis of different forms of leishmaniasis. Subsets of monocytes are distinguished by their surface markers into CD14+CD16- classical monocytes, CD14+CD16+ intermediate monocytes, and CD16++CD14low non-classical monocyte subsets. During cutaneous leishmaniasis (CL), intermediate monocyte are reported to be a source of inflammatory cytokines IL-1ß and TNF, and they express CCR2 attracting them to sites of inflammatory pathology. We examined monocyte subsets in the blood and bone marrow of patients with VL from an endemic site in Bihar, India, and found these contrasted with the roles of monocytes in CL. During VL, intermediate and non-classical CD16+ monocyte subsets expressed instead a non-inflammatory phenotype with low CCR2, high CX3CR1 and low microbicidal oxidant generation, making them more similar to patrolling monocytes than inflammatory cells. Bone marrow CD16+ monocyte subsets expressed a phenotype that might be more similar to the inflammatory subsets of CL, although our inability to obtain bone marrow from healthy donors in the endemic region hampered this interpretation Overall the data suggest that CD16+ intermediate monocyte subsets in VL patients express a phenotypes that contributes to an immunosuppressed pathologic immune state, but in contrast to CL, these do not mediate localized inflammatory responses.

Prevalence of HIV Drug Resistance Mutations among Treatment-Naive People Living with HIV in a Tertiary Care Center in India.

India has the third-largest number of people living with HIV (PLHIV) in the world. A national program provides free access to standard uniform antiretroviral therapy. However, the program is not monitored by comprehensive drug resistance surveys. The aim of this study was to determine the prevalence of HIV drug resistance mutations (DRMs) among treatment-naive PLHIV in a large antiretroviral treatment center of the national program. This cross-sectional study was done in 2017 and involved 200 consecutive treatment-naive PLHIV. A target fragment of 1,306 bp in the reverse transcriptase and protease regions was amplified. Identification of mutations and drug resistance interpretation was done by HIV Genotypic Resistance Interpretation and International Antiviral Society-USA list. Sequencing was successful in 177 samples. The majority (98.8%; 175/177) belonged to subtype C. Nineteen of 177 patients (10.7%; 95% CI: 6.2%-15.3%) had at least one major DRM. The prevalence of non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations was 10.2% (18/177). The most frequent mutations were E138A/K, A98G, K103N, V179D, and K101H/E. The prevalence of nucleoside reverse transcriptase inhibitor (NRTI) mutations was 1.1% (2/177). None of the samples had major protease inhibitor resistance mutations. The prevalence of NNRTI mutations in this study was >10%, crossing the threshold recommended by the WHO to change the NNRTI-based first-line regimen to non-NNRTI based. In 2021, the national program replaced efavirenz with dolutegravir in the first-line regimen of tenofovir, lamivudine, and efavirenz. As the majority (64%) of PLHIV in India are accessing free ART from the national program, this study highlights the need for regular nationally representative drug resistance surveys for optimizing antiretroviral regimens in the program.

Factors associated with unexplained sudden deaths among adults aged 18-45 years in India - A multicentric matched case-control study.

BACKGROUND OBJECTIVES: In view of anecdotal reports of sudden unexplained deaths in India's apparently healthy young adults, linking to coronavirus disease 2019 (COVID-19) infection or vaccination, we determined the factors associated with such deaths in individuals aged 18-45 years through a multicentric matched case-control study. METHODS: This study was conducted through participation of 47 tertiary care hospitals across India. Cases were apparently healthy individuals aged 18-45 years without any known co-morbidity, who suddenly (<24 h of hospitalization or seen apparently healthy 24 h before death) died of unexplained causes during 1 st October 2021-31 st March 2023. Four controls were included per case matched for age, gender and neighborhood. We interviewed/perused records to collect data on COVID-19 vaccination/infection and post-COVID-19 conditions, family history of sudden death, smoking, recreational drug use, alcohol frequency and binge drinking and vigorous-intensity physical activity two days before death/interviews. We developed regression models considering COVID-19 vaccination ≤42 days before outcome, any vaccine received anytime and vaccine doses to compute an adjusted matched odds ratio (aOR) with 95 per cent confidence interval (CI). RESULTS: Seven hundred twenty nine cases and 2916 controls were included in the analysis. Receipt of at least one dose of COVID-19 vaccine lowered the odds [aOR (95% CI)] for unexplained sudden death [0.58 (0.37, 0.92)], whereas past COVID-19 hospitalization [3.8 (1.36, 10.61)], family history of sudden death [2.53 (1.52, 4.21)], binge drinking 48 h before death/interview [5.29 (2.57, 10.89)], use of recreational drug/substance [2.92 (1.1, 7.71)] and performing vigorous-intensity physical activity 48 h before death/interview [3.7 (1.36, 10.05)] were positively associated. Two doses lowered the odds of unexplained sudden death [0.51 (0.28, 0.91)], whereas single dose did not. INTERPRETATION CONCLUSIONS: COVID-19 vaccination did not increase the risk of unexplained sudden death among young adults in India. Past COVID-19 hospitalization, family history of sudden death and certain lifestyle behaviors increased the likelihood of unexplained sudden death.

Wuchereria bancrofti infection is associated with progression to clinical visceral leishmaniasis in VL- endemic areas in Muzaffarpur, Bihar, India.

BACKGROUND: Co-endemicity of neglected tropical diseases (NTDs) necessitates that these diseases should be considered concomitantly to understand the relationship between pathology and to support disease management and control programs. The aims of the study were to assess the prevalence of filarial infection in asymptomatic Leishmania donovani infected individuals and the correlation of Wuchereria bancrofti infection with progression to clinical visceral leishmaniasis (VL) in Bihar, India. METHODOLOGY/PRINCIPAL FINDINGS: Within the Muzaffarpur-TMRC Health and Demographic Surveillance System (HDSS) area, a cohort of Leishmania seropositive (n = 476) or seronegative individuals (n = 1130) were sampled annually for three years for filarial infection and followed for progression to clinical VL. To corroborate the results from the cohort study, we also used a retrospective case-control study of 36 VL cases and 71 controls selected from a subset of the HDSS population to investigate the relationship between progression to clinical VL and the prevalence of filarial infection at baseline. Our findings suggest a higher probability of progression to clinical VL in individuals with a history of filarial infection: in both the cohort and case-control studies, progression to clinical VL was higher among filaria infected individuals (RR = 2.57, p = 0.056, and OR = 2.52, p = 0.046 respectively). CONCLUSION: This study describes that progression to clinical VL disease is associated with serological evidence of prior infection with W. bancrofti. The integration of disease programs for Leishmania and lymphatic filariasis extend beyond the relationship of sequential or co-infection with disease burden. To ensure elimination targets can be reached and sustained, we suggest areas of co-endemicity would benefit from overlapping vector control activities, health system networks and surveillance infrastructure.

Screening for cryptococcal antigen in asymptomatic people with HIV: urgent need in Eastern India.

OBJECTIVE: Cryptococcal meningitis (CM) is a leading cause of mortality in people with HIV (PWH). Despite recommendation by the National programme, cryptococcal antigen (CrAg) screening in PWH with CD4 + <200/µl has not been implemented in practice. Therefore, we conducted a prospective study in government funded Antiretroviral treatment centre to determine the prevalence of asymptomatic cryptococcal antigenemia in PWH with CD4 + cell count <200 cells/µl, subclinical cryptococcal meningitis in serum CrAg positive subjects and their outcome. METHOD: Serum CrAg (BIOSYNEX CryptoPS) screening was conducted in newly diagnosed asymptomatic retro-positive adults with CD4 + <200/µl between January 2021 and March 2022. We also conducted cerebrospinal fluid (CSF) CrAg testing in all PWH who were serum CrAg positive and appropriate therapy was instituted. All the enrolled participants were followed up till February 2023. RESULT: Among enrolled 142 PWH patients, 22 (15.49%) were positive for serum CrAg. Among these 22, seven (31.8%) patients had CD4 + cell count between 100 and 199 cells/µl. CSF CrAg was positive in 11 (50%) serum CrAg positive cases. Serum CrAg positivity was significantly associated with low CD4 + cell count, poor clinical stage and concomitant Pneumocystis pneumonia. However, mortality was not significantly different in Serum CrAg positive and negative PWH. None of the deaths in CrAg positive PWH was due to cryptococcal disease. CONCLUSION: Higher prevalence of cryptococcal antigenemia and subclinical CM among PWH with CD4 + cell count <200 cells/µl with good treatment outcomes with therapy reiterates the need for CrAg screening among PWH in Eastern India.

Long-term treatment outcome and mutational analysis of patients on third-line antiretroviral therapy in programmatic conditions.

BACKGROUND: In low- and middle-income countries where most patients receive standardized third-line ART through national programmes, real-world data are scarce. This study was done to assess the long-term survival, and virological and mutational outcomes of people living with HIV receiving third-line ART between July 2016 and December 2019 in an ART centre in India. METHODS: Eighty-five patients were started on third-line ART. Genotypic resistance testing to identify drug resistance mutations in the integrase, reverse transcriptase and protease genes was done at the start of third-line therapy, as well as in those who did not attain virological suppression after 12 months of therapy. RESULTS: Survival was 85% (72/85) at 12 months and 72% (61/85) at the end of follow-up in March 2022. Virological suppression was present in 82% (59/72) and 88% (59/67) at 12 months and at the end of follow-up, respectively. Five out of 13 patients who had virological failure at 12 months showed virological suppression at the end of the study. At the start of third-line therapy, 35% (14/40) and 45% (17/38) of patients had major integrase- and protease-associated mutations, respectively, even though they had never been on integrase inhibitor-based regimens. At 1 year follow-up, among those failing third-line therapy, 33% (4/12) of patients had major integrase mutations, but none had major protease mutations. CONCLUSIONS: This study demonstrates good long-term outcome in patients on standardized third-line ART in programmatic conditions with very few mutations in those failing the therapy.

Rhizopus homothallicus rhino-orbital-cerebral mucormycosis: Six cases from a tertiary care Centre, North India.

OBJECTIVE: To report six cases of Rhizopus homothallicus rhino-orbital-cerebral mucormycosis in North India between April 2021 and July 2021. CASE DETAILS: All six patients had diabetes, concomitant SARS-CoV-2 infection, a history of oxygen requirement and steroid intake. Among these six cases 4 were female. All patients presented with sinus pain and peri-orbital swelling. COVID-19-associated mucormycosis (CAM) was diagnosed based on microbiological examination of the biopsied tissue, and its staging was determined radiologically by CT and MRI. Three patients were in stage III-C, the others were in stage II-C, II-D and IV-A. A multidisciplinary team treated the patients with extensive surgical debridement of the affected tissue, correction of predisposing comorbidities and administration of an antifungal agents. Patients were followed up for 6 months with routine direct nasal endoscopy to check the sinonasal cavity for any recurrence. All the six patients survived at 6 months of follow-up. CONCLUSION: A timely initiated multidisciplinary team-based approach can reduce the mortality in rhino-orbital-cerebral mucormycosis cases caused by R. homothallicus.

Magnetic resonance imaging spectrum of COVID-associated rhino-orbital-cerebral mucormycosis and assessment of anatomical severity.

OBJECTIVES: To describe the extent and imaging findings of COVID-associated rhino-orbital-cerebral mucormycosis on magnetic resonance imaging and to evaluate the value of MRI severity score in grading the extent of involvement. METHODS: Proven cases of ROCM with a history of concurrent or recently (<6 weeks) treated COVID-19 underwent MRI at the initial presentation. Findings were charted for each anatomical structure and the extent of involvement was scored for sinonasal, extra-sinus soft tissues, orbits, and brain. MR severity score was defined by summing up the individual scores of each compartment (sinonasal 20, orbital 20, soft tissue 10, and brain 10) and a total score out of 60 was assigned. RESULTS: A total of 47 patients were included in our study with variable involvement of sinonasal compartment (n = 43), extra-sinus soft tissue (n = 25), orbits (n = 23), and brain (n = 17). In the sinonasal compartment, T2, DWI, and post-contrast T1 were the most useful sequences. A significantly higher mean sinonasal score was associated with mortality (p = 0.007). In the orbits, a combination of STIR (orbital fat and extraconal muscles), DWI (optic nerves), and post-contrast images (superior ophthalmic vein) were the most accurate sequences. A higher mean orbital score was associated with vision loss (p = 0.001). Patients with uncontrolled diabetes had greater extent of cranial involvement. CONCLUSION: A combination of magnetic resonance sequences is required to correctly evaluate the involvement of individual structures and thus to assign the correct MR scoring. The proposed MR severity score can effectively and objectively evaluate the severity of COVID-associated ROCM.

COVID-19-associated Mucormycosis: A clinico-epidemiological study.

BACKGROUND: There was an unprecedented increase in COVID-19-associated-Mucormycosis (CAM) cases during the second pandemic wave in India. METHODS: This observational study was done to know the epidemiological profile of CAM cases andincluded all patients admitted with mucormycosis between May 2021 and July 2021. RESULTS: Out of the enrolled 208 CAM cases (either SARS-CoV-2 RT-PCR or serology positive), 204, three and one had rhino-orbital-cerebral, pulmonary and gastrointestinal mucormycosis, respectively. 95.7 % of the patients had diabetes, out of which 42.3 % were recently diagnosed. Mean HbA1c was 10.16 ± 2.56 %. 82.5 % of the patients were unvaccinated. During their COVID-19 illness, 86.5 % were prescribed antibiotics, 84.6 % zinc preparations, 76.4 % ivermectin, and 64.9 % steroids, while only 39.5 % required oxygen therapy. The frequency of blood groups A, B, O and AB in our CAM patients was 29.5 %, 18.9 %, 38.9 % &12.6 %, respectively. At three months follow up, 60 (28.8 %) patients died, four (1.9 %) stopped antifungal treatment, and 144(69.23 %) were on antifungal treatment. 55 % (n = 33) of deaths occurred within 15 days of admission. Mortality was significantly associated with higher age, RT-PCR positive for SARS-CoV-2, raised serum creatinine and alkaline phosphatase during treatment. At 6 months follow-up, eight more patients died, three due to chronic kidney disease, four patients who had stopped treatment and one patient who was on a ventilator due to COVID-19 associated pneumonia and the rest 140(67.3 %) survived. CONCLUSION: Uncontrolled hyperglycemia, SARS-CoV-2 infection, rampant use of antibiotics, zinc supplementation and steroids were some of the risk factors for mucormycosis. Despite the overwhelming number of patients with an uncommon disease like mucormycosis, the six months mortality was much lower than expected.

Geographical Variability in Paromomycin Pharmacokinetics Does Not Explain Efficacy Differences between Eastern African and Indian Visceral Leishmaniasis Patients.

INTRODUCTION: Intramuscular paromomycin monotherapy to treat visceral leishmaniasis (VL) has been shown to be effective for Indian patients, while a similar regimen resulted in lower efficacy in Eastern Africa, which could be related to differences in paromomycin pharmacokinetics. METHODS: Pharmacokinetic data were available from two randomized controlled trials in VL patients from Eastern Africa and India. African patients received intramuscular paromomycin monotherapy (20 mg/kg for 21 days) or combination therapy (15 mg/kg for 17 days) with sodium stibogluconate. Indian patients received paromomycin monotherapy (15 mg/kg for 21 days). A population pharmacokinetic model was developed for paromomycin in Eastern African and Indian VL patients. RESULTS: Seventy-four African patients (388 observations) and 528 Indian patients (1321 observations) were included in this pharmacokinetic analysis. A one-compartment model with first-order kinetics of absorption and elimination best described paromomycin in plasma. Bioavailability (relative standard error) was 1.17 (5.18%) times higher in Kenyan and Sudanese patients, and 2.46 (24.5%) times higher in Ethiopian patients, compared with Indian patients. Ethiopian patients had an approximately fourfold slower absorption rate constant of 0.446 h-1 (18.2%). Area under the plasma concentration-time curve for 24 h at steady-state (AUCτ,SS) for 15 mg/kg/day (median [interquartile range]) was higher in Kenya and Sudan (172.7 µg·h/mL [145.9-214.3]) and Ethiopia (230.1 µg·h/mL [146.3-591.2]) compared with India (97.26 µg·h/mL [80.83-123.4]). CONCLUSION: The developed model provides detailed insight into the pharmacokinetic differences among Eastern African countries and India, however the resulting differences in paromomycin exposure do not seem to explain the geographical differences in paromomycin efficacy in the treatment of VL patients.

Xenodiagnosis to evaluate the infectiousness of humans to sandflies in an area endemic for visceral leishmaniasis in Bihar, India: a transmission-dynamics study.

BACKGROUND: Visceral leishmaniasis, also known on the Indian subcontinent as kala-azar, is a fatal form of leishmaniasis caused by the protozoan parasite Leishmania donovani and transmitted by the bites of the vector sandfly Phlebotomus argentipes. To achieve and sustain elimination of visceral leishmaniasis, the transmission potential of individuals exposed to L donovani from across the infection spectrum needs to be elucidated. The aim of this study was to evaluate the relative infectiousness to the sandfly vector of patients with visceral leishmaniasis or post-kala-azar dermal leishmaniasis, before and after treatment, and individuals with asymptomatic infection. METHODS: In this prospective xenodiagnosis study done in Muzaffarpur district of Bihar, India, we included patients with clinically confirmed active visceral leishmaniasis or post-kala-azar dermal leishmaniasis who presented to the Kala-Azar Medical Research Center. These participants received treatment for L donovani infection. We also included asymptomatic individuals identified through a serosurvey of 17 254 people living in 26 high-transmission clusters. Eligible participants were aged 12-64 years, were HIV negative, and had clinically or serologically confirmed L donovani infection. During xenodiagnosis, the forearms or lower legs of participants were exposed to 30-35 female P argentipes sandflies for 30 min. Blood-engorged flies were held in an environmental cabinet at 28°C and 85% humidity for 60-72 h, after which flies were dissected and evaluated for L donovani infection by microscopy and quantitative PCR (qPCR). The primary endpoint was the proportion of participants with visceral leishmaniasis or post-kala-azar dermal leishmaniasis, before and after treatment, as well as asymptomatic individuals, who were infectious to sandflies, with a participant considered infectious if promastigotes were observed in one or more individual flies by microscopy, or if one or more of the pools of flies tested positive by qPCR. FINDINGS: Between July 12, 2016, and March 19, 2019, we recruited 287 individuals, including 77 with active visceral leishmaniasis, 26 with post-kala-azar dermal leishmaniasis, and 184 with asymptomatic infection. Of the patients with active visceral leishmaniasis, 42 (55%) were deemed infectious to sandflies by microscopy and 60 (78%) by qPCR before treatment. No patient with visceral leishmaniasis was found to be infectious by microscopy at 30 days after treatment, although six (8%) were still positive by qPCR. Before treatment, 11 (42%) of 26 patients with post-kala-azar dermal leishmaniasis were deemed infectious to sandflies by microscopy and 23 (88%) by qPCR. Of 23 patients who were available for xenodiagnosis after treatment, one remained infectious to flies by qPCR on the pooled flies, but none remained positive by microscopy. None of the 184 asymptomatic participants were infectious to sandflies. INTERPRETATION: These findings confirm that patients with active visceral leishmaniasis and patients with post-kala-azar dermal leishmaniasis can transmit L donovani to the sandfly vector and suggest that early diagnosis and treatment could effectively remove these individuals as infection reservoirs. An important role for asymptomatic individuals in the maintenance of the transmission cycle is not supported by these data. FUNDING: Bill & Melinda Gates Foundation.

Anti-Interleukin-10 Unleashes Transcriptional Response to Leishmanial Antigens in Visceral Leishmaniasis Patients.

Visceral leishmaniasis (VL; Leishmania donovani) cases produce interferon-γ and tumor necrosis factor in response to soluble leishmanial antigen (SLA) in whole-blood assays. Using transcriptional profiling, we demonstrate the impact of interleukin-10 (IL-10), a cytokine implicated in VL, on this response. SLA stimulation identified 28 differentially expressed genes (DEGs), 17/28 in a single network with TNF as hub. SLA plus anti-IL-10 produced 454 DEGs, 292 in a single network with TNF, IFNG, NFKBIA, IL6, and IL1B as hubs in concert with a remarkable chemokine/cytokine storm. Our data demonstrate the singular effect of IL-10 as a potent immune modulator in VL.

The utility of banana peel extract agar in the presumptive identification of Cryptococcus neoformans.

We prepared a newer growth medium, banana peel extract agar (BPEA) containing the extracts of chopped banana peels for the selective cultivation of Cryptococcus neoformans. Over the medium, the growth resulted in the development of light to the dark brown coloured colonies indicating the chromogenic potential of the BPEA. The organism grown over BPEA was subsequently confirmed as C. neoformans by phenotypic as well as by molecular method. This medium, being cost-effective, may be used in resource-poor settings of the developing or underdeveloped countries for selective isolation of C. neoformans.

Factors affecting disclosure of HIV-positive serostatus among people living with HIV/AIDS attending an antiretroviral therapy center of Eastern India.

BACKGROUND: HIV serostatus disclosure plays an important role in reducing the risk of HIV transmission. However, its negative effects may include rejection, assault, separation, divorce, stigma, and discrimination. OBJECTIVES: This study was undertaken to find out the proportion of HIV-positive serostatus disclosure to any family member and different factors influencing disclosure among people living with HIV/AIDS (PLWHA). METHODS: A cross-sectional study was conducted among all patients aged 18-49 years with confirmed HIV infection registered at the antiretroviral therapy center of a tertiary care hospital in eastern part of Uttar Pradesh, India, for the duration of 1 year, from July 2017 to June 2018. RESULTS: Most of the respondents were aged 30-49 years (79.9%), male (63.2%), married (85.4%), rural residents (60.4%), Hindu (96.5%), literate (84%), employed/driver (61.8%), and belonged to lower/lower middle class (62.6%). The rate of disclosure of HIV-positive status to any family member was quite high in this study (238/288 or 82.6%), among which 92.9% (221/238) to the spouse only. The number of sexual partners before disclosure, educational status, and socioeconomic status of the respondents were found to be independent predictors of disclosure of HIV-positive status to any family member (P < 0.05). CONCLUSIONS: This study indicates the need of giving more emphasis on creating awareness regarding the importance of HIV serostatus disclosure to any family member, especially to spouse, and encourage all PLWHA in the community to disclose their status. Effective strategies also need to be evolved that will target those not likely to disclose their status to anybody.

Type I Interferons Suppress Anti-parasitic Immunity and Can Be Targeted to Improve Treatment of Visceral Leishmaniasis.

Type I interferons (IFNs) play critical roles in anti-viral and anti-tumor immunity. However, they also suppress protective immune responses in some infectious diseases. Here, we identify type I IFNs as major upstream regulators of CD4+ T cells from visceral leishmaniasis (VL) patients. Furthermore, we report that mice deficient in type I IFN signaling have significantly improved control of Leishmania donovani, a causative agent of human VL, associated with enhanced IFNγ but reduced IL-10 production by parasite-specific CD4+ T cells. Importantly, we identify a small-molecule inhibitor that can be used to block type I IFN signaling during established infection and acts synergistically with conventional anti-parasitic drugs to improve parasite clearance and enhance anti-parasitic CD4+ T cell responses in mice and humans. Thus, manipulation of type I IFN signaling is a promising strategy for improving disease outcome in VL patients.