scholarly journals Preclinical validation of a second generation leishmanization vaccine against vector transmitted fatal visceral leishmaniasis

2020 ◽  
Author(s):  
Subir Karmakar ◽  
Nevien Ismail ◽  
Fabiano Oliveira ◽  
James Oristian ◽  
Wen Wei Zhang ◽  
...  
Keyword(s):  
Immune Response ◽  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Leishmania Major ◽  
Protective Efficacy ◽  
Sand Fly ◽  
Endemic Region ◽  
Cytokines And Chemokines ◽  
Human Leishmaniasis ◽  
Strong Candidate

AbstractVisceral Leishmaniasis (VL) is fatal if untreated. There is no licensed vaccine available against human leishmaniasis. We recently demonstrated protection in mice against L. major infection using a CRISPR genome edited attenuated Leishmania major strain (LmCen−/−). Here, as a pre-clinical step, we evaluated the protective efficacy of LmCen−/− against VL induced by sand fly transmitted Leishmania donovani in hamsters. Intradermal immunization of hamsters with LmCen−/− did not develop any lesion; while still priming a pro-inflammatory immune response. When challenged with L. donovani either by intradermal needle injection or by infected sand flies, LmCen−/−-immunized hamsters were protected, not showing spleen or liver pathology averting VL fatality compared to control animals. Spleen cells from LmCen−/− immunized and infected sand fly challenged hamsters produced significantly higher Th1-associated cytokines and chemokines including IFN-γ and TNF-α, and significantly reduced expression of the anti-inflammatory cytokines IL-10 and IL-21, compared to non-immunized challenged animals. We further developed a GLP-grade LmCen−/− which showed equal protection as laboratory-grade LmCen−/− parasites in hamsters. Importantly, GLP-grade LmCen−/− parasites also induced a proinflammatory immune response in the PBMCs isolated from healthy people living in non-endemic and endemic for VL as well as cured VL people living in endemic region. Together, this study demonstrates that the LmCen−/− parasites are safe and efficacious against VL and it is a strong candidate vaccine to be tested in a human clinical trial.

scholarly journals Preclinical validation of a live attenuated dermotropic Leishmania vaccine against vector transmitted fatal visceral leishmaniasis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Subir Karmakar ◽  
Nevien Ismail ◽  
Fabiano Oliveira ◽  
James Oristian ◽  
Wen Wei Zhang ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Leishmania Major ◽  
Intradermal Injection ◽  
Human Clinical Trial ◽  
Endemic Region ◽  
Tnf Α ◽  
Good Laboratory ◽  
Ifn Γ ◽  
Strong Candidate

AbstractVisceral Leishmaniasis (VL), a potentially fatal disease is caused by Leishmania donovani parasites with no vaccine available. Here we produced a dermotropic live attenuated centrin gene deleted Leishmania major (LmCen−/−) vaccine under Good Laboratory Practices and demonstrated that a single intradermal injection confers robust and durable protection against lethal VL transmitted naturally via bites of L. donovani-infected sand flies and prevents mortality. Surprisingly, immunogenicity characteristics of LmCen−/− parasites revealed activation of common immune pathways like L. major wild type parasites. Spleen cells from LmCen−/− immunized and L. donovani challenged hamsters produced significantly higher Th1-associated cytokines including IFN-γ, TNF-α, and reduced expression of the anti-inflammatory cytokines like IL-10, IL-21, compared to non-immunized challenged animals. PBMCs, isolated from healthy people from non-endemic region, upon LmCen−/− infection also induced more IFN-γ compared to IL-10, consistent with our immunogenicity data in LmCen−/− immunized hamsters. This study demonstrates that the LmCen−/− parasites are safe and efficacious against VL and is a strong candidate vaccine to be tested in a human clinical trial.

DETECTION OF LEISHMANIA INFECTION IN STRAY DOGS IN HUMAN LEISHMANIASIS ENDEMIC AREA IN MYMENSINGH DISTRICT WITH ITS POSSIBLE PUBLIC HEALTH SIGNIFICANCE IN BANGLADESH

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
M. A. Hossen
Keyword(s):  
Visceral Leishmaniasis ◽  
Asymptomatic Carrier ◽  
Asymptomatic Infection ◽  
Reservoir Host ◽  
Sand Fly ◽  
Leishmania Infection ◽  
Endemic Region ◽  
Stray Dogs ◽  
Human Leishmaniasis ◽  
Strip Test

Background: Leishmaniasis is primarily caused by two species of Leishmania (L. donovani and L. infantum) of which clinical infection with L. infantum has been recognized in both humans and dogs as zoonotic disease with dogs as the main reservoir hosts in the Mediterranean, the Middle East, Asia and South America. Although L. donovani has been associated with both clinical and asymptomatic infection in humans but it is still associated with asymptomatic infection in dogs in Indian sub-continent without any evidence of zoonotic infection. Objectives: The objective of this research was to investigate the potentiality of dog as reservoir host for visceral leishmaniasis in the human leishmaniasis endemic regions in Bangladesh. Materials and Methods: A total of 20 stray dogs in the human VL endemic areas of Mymensingh district were captured for the detection VL during the period of November 2010 to May 2011. The dipstick test rK39 (Bios International; n = 20), Giemsa’s stained impression smears of liver and spleen (n = 6) and PCR with the tissue of liver and spleen (n = 6) were tested as per manufacturer instructions and conventional standard methods. Results: Out of 20 stray dogs examined, 4 (20.0%) were positive for L. donovani infection with rK39 strip test. Of the six randomly selected dogs tested with Modified Giemsa’s stained of impression smears of spleen and liver showed 2 (33.33%) positive whereas PCR technique detected 5 (83.33%) positive for L. donovani. Results of PCR showed 145bp amplicon, specific for L. donovani infection in 83.33% stray dogs. Conclusions: This study reveals that a high percentage of L. donovani asymptomatic carrier infections occur in dogs and evidence indicates that dogs and humans may potentially serve as a source of infection to sand fly vectors and accordingly dogs can be recognized as a probable animal reservoir for the Leishmania infection in the endemic region in Bangladesh. However, further studies are required to determine the ability of dogs to transmit the L. donovani to the vector sand fly in nature and its evidence on ‘One Health’ perspectives. Keywords: Visceral leishmaniasis, Endemic region, Stray dogs, rK39 strip test, Giemsa’s stained liver and spleen impression smears, PCR, Reservoir host, Mymensingh

Lupeol induces immunity and protective efficacy in a murine model against visceral leishmaniasis

Parasitology ◽  
2019 ◽  
Vol 146 (11) ◽  
pp. 1440-1450 ◽  
Author(s):  
Gurpreet Kaur ◽  
Kalpana Chauhan ◽  
Sukhbir Kaur
Keyword(s):  
Nitric Oxide ◽  
Immune Response ◽  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Protective Efficacy ◽  
Parasite Burden ◽  
Delayed Type Hypersensitivity ◽  
Reference Drug ◽  
Th2 Immune Response

AbstractThe available chemotherapeutics for the cure of visceral leishmaniasis (VL) are linked with many detrimental effects. Moreover, VL is associated with the suppression of protective Th1 immune response of the host and induction of disease exaggerating Th2 immune response. Therefore, there is an urgent requirement of therapeutics which can augment the immune status of the host to cure this disease. In the current investigation, the antileishmanial potential of lupeol was monitored in vitro and in vivo in inbred BALB/c mice against Leishmania donovani. Lupeol showed potent antipromastigote activity via arresting parasites at sub G0/G1 phase in vitro. Lupeol significantly decreased the splenic parasite burden by inducing strong delayed-type hypersensitivity responses in contrary to untreated infected animals. The therapeutic efficacy of lupeol was observed to be similar to the reference drug, AmB. Treatment of infected animals with lupeol depicted enhanced levels of T cells and Th1 cytokines in contrast to only infected controls. Further lupeol treatment upregulated the levels of nuclear factor κ B and nitric oxide synthase genes and elevated the production of reactive oxygen species and nitric oxide. Unlike AmB, lupeol-treated infected animals did not show any toxicity. These findings are promising and indicate that lupeol can serve as a prototype drug for the cure of VL.

scholarly journals Molecular detection of Leishmania donovani, Leishmania major, and Trypanosoma species in Sergentomyia squamipleuris sand flies from a visceral leishmaniasis focus in Merti sub-County, eastern Kenya

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Barrack O. Owino ◽  
Jackline Milkah Mwangi ◽  
Steve Kiplagat ◽  
Hannah Njiriku Mwangi ◽  
Johnstone M. Ingonga ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Mus Musculus ◽  
Blood Meal ◽  
Leishmania Donovani ◽  
Leishmania Major ◽  
Sand Fly ◽  
Health Concern ◽  
Sand Flies ◽  
Reservoir Hosts ◽  
Blood Meals

Abstract Background Visceral leishmaniasis (VL) and zoonotic cutaneous leishmaniasis (ZCL) are of public health concern in Merti sub-County, Kenya, but epidemiological data on transmission, vector abundance, distribution, and reservoir hosts remain limited. To better understand the disease and inform control measures to reduce transmission, we investigated the abundance and distribution of sand fly species responsible for Leishmania transmission in the sub-County and their blood-meal hosts. Methods We conducted an entomological survey in five villages with reported cases of VL in Merti sub-County, Kenya, using CDC miniature light traps and castor oil sticky papers. Sand flies were dissected and identified to the species level using standard taxonomic keys and PCR analysis of the cytochrome c oxidase subunit 1 (cox1) gene. Leishmania parasites were detected and identified by PCR and sequencing of internal transcribed spacer 1 (ITS1) genes. Blood-meal sources of engorged females were identified by high-resolution melting analysis of vertebrate cytochrome b (cyt-b) gene PCR products. Results We sampled 526 sand flies consisting of 8 species, Phlebotomus orientalis (1.52%; n = 8), and 7 Sergentomyia spp. Sergentomyia squamipleuris was the most abundant sand fly species (78.71%; n = 414) followed by Sergentomyia clydei (10.46%; n = 55). Leishmania major, Leishmania donovani, and Trypanosoma DNA were detected in S. squamipleuris specimens. Humans were the main sources of sand fly blood meals. However, we also detected mixed blood meals; one S. squamipleuris specimen had fed on both human and mouse (Mus musculus) blood, while two Ph. orientalis specimens fed on human, hyrax (Procavia capensis), and mouse (Mus musculus) blood. Conclusions Our findings implicate the potential involvement of S. squamipleuris in the transmission of Leishmania and question the dogma that human leishmaniases in the Old World are exclusively transmitted by sand flies of the Phlebotomus genus. The presence of Trypanosoma spp. may indicate mechanical transmission, whose efficiency should be investigated. Host preference analysis revealed the possibility of zoonotic transmission of leishmaniasis and other pathogens in the sub-County. Leishmania major and L. donovani are known to cause ZCL and VL, respectively. However, the reservoir status of the parasites is not uniform. Further studies are needed to determine the reservoir hosts of Leishmania spp. in the area.

scholarly journals Clinical and laboratory profiles of visceral leishmaniasis among adult patients admitted to Felege Hiwot Hospital, Bahir Dar, Ethiopia

2021 ◽  
Vol 9 ◽  
pp. 205031212110367
Author(s):  
Berhanu Tarekegn ◽  
Ayanaw Tamene
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Clinical Presentation ◽  
Winter Season ◽  
Adult Patients ◽  
Sand Fly ◽  
Timely Initiation ◽  
Vector Borne Disease ◽  
Vector Borne ◽  
Endemic Areas

Background: Visceral leishmaniasis is a vector-borne disease caused by Leishmania donovani transmitted by sand fly species. It is the third most common vector-borne disease globally. Visceral leishmaniasis is endemic in Ethiopia with an estimated annual incidence ranging from 3700 to 7400 cases. This research aimed to assess the clinical presentations and laboratory profiles of visceral leishmaniasis for early diagnosis and timely initiation of management. Objective: To describe the clinical and laboratory manifestation and diagnostic modalities of visceral leishmaniasis among adult patients admitted to Felege Hiwot Hospital, from 1 September 2016 to 30 August 2019. Method: Institution-based retrospective cross-sectional study was conducted among 141 patients admitted to Felege Hiwot Hospital from 1 September 2016 to 30 August 2019. Descriptive statistics were used to describe the clinical presentation and laboratory profiles of patients with visceral leishmaniasis. Results: Among a total of 141 enrolled patients in the study, males were affected 13-fold. Most of them were travelers to endemic areas during the winter season for labor work. The mean duration of illness was 48 days. Common symptoms were fever (96.5%), weightless (82.5%), jaundice (18.4%), vomiting/diarrhea (13.5%), and bleeding episodes (11.3%). Splenomegaly was seen in 98.6%, ascites in 35.5%, and lymphadenopathy in 9.9%. Lymphadenopathy was seen significantly in HIV patients (40%). Anemia was seen in 95%, thrombocytopenia in 90.2%, leukopenia in 86.4%, and pancytopenia in 79.4%. Half of the patients had coinfection. Neutropenic sepsis was seen in 21.3%. The diagnosis was made by tissue aspiration in 65% of patients. Conclusion: The majority of patients who were diagnosed to have visceral leishmaniasis were young male adults who traveled to the endemic areas seasonally. Fever and splenomegaly were seen as the commonest clinical presentation. Lymphadenopathy occurred in high frequency among HIV co-infected patients. Anemia was the commonest hematologic finding.

scholarly journals gp63 in Stable Cationic Liposomes Confers Sustained Vaccine Immunity to Susceptible BALB/c Mice Infected with Leishmania donovani

2008 ◽  
Vol 76 (3) ◽  
pp. 1003-1015 ◽  
Author(s):  
Swati Bhowmick ◽  
Rajesh Ravindran ◽  
Nahid Ali
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Protective Efficacy ◽  
Cationic Liposomes ◽  
Interleukin 4 ◽  
Th2 Response ◽  
Parasitic Burden ◽  
Ifn Γ ◽  
Dose Dependent

ABSTRACT Visceral leishmaniasis is deadly if not treated, and development of a vaccine with long-term immunity remains a challenge. In this study, we showed that cationic distearoyl phosphatidylcholine (DSPC) liposomes, when used as vaccine adjuvant with the immunodominant 63-kDa glycoprotein (gp63) of Leishmania donovani promastigotes, induced significant protection against progressive visceral leishmaniasis in susceptible BALB/c mice. gp63 used without adjuvant elicited partial protection but in association with liposomes exhibited marked resistance in both the livers and spleens of the mice challenged 10 days after the last vaccination. The protective efficacy of liposomal gp63 vaccination was dose dependent, with 2.5 μg of protein showing optimal protection. The immunity conferred by this vaccine formulation was durable, as mice challenged 12 weeks after immunization were still protected, and the infection was controlled for at least 3 months postchallenge. Production of gamma interferon (IFN-γ) and interleukin-4 (IL-4) by splenic T cells, and of serum immunoglobulin G1 (IgG1) and IgG2a following immunization, suggested that a mixed Th1/Th2 response had been induced following immunization. However, control of disease progression and parasitic burden in mice vaccinated with gp63 in cationic DSPC liposomes was associated with enhancement of antigen-specific IFN-γ and downregulation of IL-4, demonstrating a Th1 bias. Long-term immunity elicited by this vaccine corresponded to, in addition to the presence of antigen-specific Th1, CD8+ T-cell responses. Our results demonstrated that stable cationic liposomes containing gp63 acted as a potent adjuvant for protein antigen to induce long-term protection against L. donovani that represents an alternative to DNA vaccination.

scholarly journals Study of Visceral Leishmaniasis (Kala-azar) in Children of Nepal

2009 ◽  
Vol 29 (2) ◽  
pp. 67-73 ◽  
Author(s):  
Durga Datt Joshi
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Research Work ◽  
Case Fatality ◽  
Zoonotic Disease ◽  
Morbidity And Mortality ◽  
Sand Fly ◽  
Epidemiological Surveillance ◽  
Mortality Data ◽  
Kala Azar

Introduction: Visceral leishmaniasis (VL) or Kala-azar is a potentially fatal vector-borne (sand fly phlebotomies spp) zoonotic disease caused by a protozoan parasite, Leishmania donovani. In Nepal, the disease is restricted to the Eastern Terai region which lies adjacent to the Bihar state of India. Although leishmaniasis is regarded as a significant health problem in Nepal by the Ministry of Health, there is no active case detection programme in the country. Objective: Objectives of this study were to determine the up-to-date morbidity and mortality trend for VL in children of Nepal. Method: The epidemiological surveillance team from the NZFHRC visited to eight zonal hospitals in Terai region during the month from September to December of each year 2003 to 2007. The morbidity and mortality data up to the year 2007 were collected every year. The team has also collected 66 blood serum samples of which 18 samples from children were collected for the diagnosis. Results: A total 25890 cases with 599 deaths were reported during the year 1980-2006. The case fatality rate (CFR) varied from 0.23% to 13.2%. Districtwise analysis showed that, during 2003, highest incidence was in Mahottari district (184/100,000), followed by Sarlahi (100/100,000) and Sunsari (96/100,000). The highest CFR was in Dhanusha (2.9%) followed by Bara (2.4%) and Saptari (2.0%). Majority (70.9%) of persons affected by VL were aged 15 years and above, followed by 10-14 years (13.9%), 5-9 years (11.9%) and 1-4 years (3.3%). VL cases recorded from different district of Nepal for the year 2004, 2005, 2006 and 2007 are recorded. CFR for the year 2004, 2005, 2006 and 2007 were 3.2%, 3.7%, 16.67% and 11.42% respectively. Conclusions: There should be regular surveillance research work to be carried out in endemic area. Mass public health education, to make the people aware about preventive aspects of the disease is important. The possibility of the existence of animal reservoirs as zoonotic disease should also be considered. This disease is very much serious in children below 15 years of age both in male and female, therefore it is essential to have paediatrician post at least in all VL six endemic districts. Key words: Epidemiology, Leishmaniasis, Kala-azar, Sandfly   doi: 10.3126/jnps.v29i2.2041 J. Nepal Paediatr. Soc. Vol 29, No. 2, pp.67-73

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