Survival of Loa loa following transplantation from drills (Mandrillus leucophaeus) into jirds (Meriones unguiculatus): parasitology and pathology

1982 ◽  
Vol 76 (6) ◽  
pp. 778-782 ◽  
Author(s):  
C.D. Mackenzie ◽  
R.R. Suswillo ◽  
D.A. Denham
Keyword(s):  
Meriones Unguiculatus ◽  
Loa Loa ◽  
Mandrillus Leucophaeus

Attempts to infect jirds (Meriones unguiculatus) with Wuchereria bancrofti, Onchocerca volvulus, Loa loa loa and Mansonella ozzardi

1977 ◽  
Vol 51 (2) ◽  
pp. 132-134 ◽  
Author(s):  
R. R. Suswillo ◽  
G. S. Nelson ◽  
R. Muller ◽  
P. B. McGreevy ◽  
B. O. L. Duke ◽  
...  
Keyword(s):  
Wuchereria Bancrofti ◽  
Meriones Unguiculatus ◽  
Onchocerca Volvulus ◽  
Loa Loa

scholarly journals A rapid, parasite-dependent cellular response to Dirofilaria immitis in the Mongolian jird (Meriones unguiculatus)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Christopher C. Evans ◽  
Katherine M. Day ◽  
Yi Chu ◽  
Bridget Garner ◽  
Kaori Sakamoto ◽  
...  
Keyword(s):  
Cellular Response ◽  
Dirofilaria Immitis ◽  
Cell Attachment ◽  
Early Response ◽  
Meriones Unguiculatus ◽  
Filarial Parasite ◽  
Immune Mediated ◽  
Secretory Products ◽  
Species Specific

Abstract Background The Mongolian jird (Meriones unguiculatus) has long been recognized as a permissive host for the filarial parasite Brugia malayi; however, it is nonpermissive to another filarial parasite, canine heartworm (Dirofilaria immitis). By elucidating differences in the early response to infection, we sought to identify mechanisms involved in the species-specific clearance of these parasites. We hypothesized that the early clearance of D. immitis in intraperitoneal infection of the jird is immune mediated and parasite species dependent. Methods Jird peritoneal exudate cells (PECs) were isolated and their attachment to parasite larvae assessed in vitro under various conditions: D. immitis and B. malayi cultured separately, co-culture of both parasites, incubation before addition of cells, culture of heat-killed parasites, and culture with PECs isolated from jirds with mature B. malayi infection. The cells attaching to larvae were identified by immunohistochemistry. Results In vitro cell attachment to live D. immitis was high (mean = 99.6%) while much lower for B. malayi (mean = 5.56%). This species-specific attachment was also observed when both filarial species were co-cultured, with no significant change from controls (U(9, 14) = 58.5, p = 0.999). When we replicated these experiments with PECs derived from jirds subcutaneously infected with B. malayi, the results were similar (99.4% and 4.72% of D. immitis and B. malayi, respectively, exhibited cell attachment). Heat-killing the parasites significantly reduced cell attachment to D. immitis (mean = 71.9%; U(11, 14) = 7.5, p < 0.001) while increasing attachment to B. malayi (mean = 16.7%; U(9, 15) = 20, p = 0.002). Cell attachment to both species was reduced when larvae were allowed a 24-h pre-incubation period prior to the addition of cells. The attaching cells were identified as macrophages by immunohistochemistry. Conclusions These results suggest a strongly species-dependent response from which B. malayi could not confer protection by proxy in co-culture. The changes in cell attachment following heat-killing and pre-incubation suggest a role for excretory/secretory products in host immune evasion and/or antigenicity. The nature of this attachment is the subject of ongoing study and may provide insight into filarial host specificity.

scholarly journals Validation of loop-mediated isothermal amplification for the detection of Loa loa infection in Chrysops spp in experimental and natural field conditions

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Glory Ngongeh Amambo ◽  
Raphael Awah Abong ◽  
Fanny Fri Fombad ◽  
Abdel Jelil Njouendou ◽  
Franck Nietcho ◽  
...  
Keyword(s):  
Lamp Assay ◽  
Isothermal Amplification ◽  
Field Conditions ◽  
Infection Rates ◽  
Loa Loa ◽  
Significant Drop ◽  
Natural Field ◽  
North West ◽  
Loop Mediated Isothermal Amplification ◽  
The North

Abstract Background The mass drug administration of ivermectin for onchocerciasis control has contributed to a significant drop in Loa loa microfilaria loads in humans that has, in turn, led to reduction of infection levels in Chrysops vectors. Accurate parasite detection is essential for assessing loiasis transmission as it provides a potential alternative or indirect strategy for addressing the problem of co-endemic loiasis and lymphatic filariasis through the Onchocerciasis Elimination Programme and it further reflects the true magnitude of the loiasis problem as excess human mortality has been reported to be associated with the disease. Although microscopy is the gold standard for detecting the infection, the sensitivity of this method is compromised when the intensity of infection is low. The loop-mediated isothermal amplification (LAMP) assay of parasite DNA is an alternative method for detecting infection which offers operational simplicity, rapidity and versatility of visual readout options. The aim of this study was to validate the Loa loa LAMP assay for the detection of infected Chrysops spp. under experimental and natural field conditions. Methods Two sets of 18 flies were fed on volunteers with either a low (< 10 mf/ml) or high (> 30,000mf/ml) microfilarial load. The fed flies were maintained under laboratory conditions for 14 days and then analysed using LAMP for the detection of L. loa infection. In addition, a total of 9270 flies were collected from the north-west, east, and south-west regions (SW 1 and 2) of Cameroon using sweep nets and subjected to microscopy (7841 flies) and LAMP (1291 flies plus 138 nulliparous flies) analyses. Results The LAMP assay successfully detected parasites in Chrysops fed on volunteers with both low and high microfilariaemic loads. Field validation and surveillance studies revealed LAMP-based infection rates ranging from 0.5 to 31.6%, with the lowest levels in SW 2 and the highest infection rates in SW 1. The LAMP assay detected significantly higher infection rates than microscopy in four of the five study sites. Conclusion This study demonstrated the potential of LAMP as a simple surveillance tool. It was found to be more sensitive than microscopy for the detection of experimental and natural L. loa infections in Chrysops vectors.

scholarly journals Feasibility of onchocerciasis elimination using a “test-and-not-treat” strategy in Loa loa co-endemic areas

2020 ◽  
Author(s):  
David J Blok ◽  
Joseph Kamgno ◽  
Sebastien D Pion ◽  
Hugues C Nana-Djeunga ◽  
Yannick Niamsi-Emalio ◽  
...  
Keyword(s):  
Adverse Events ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Treatment Duration ◽  
Loa Loa ◽  
Serious Adverse Events ◽  
Endemic Areas ◽  
The Individual ◽  
The Impact ◽  
Main Strategy

Abstract Background Mass drug administration (MDA) with ivermectin is the main strategy for onchocerciasis elimination. Ivermectin is generally safe but associated with serious adverse events in individuals with high Loa loa microfilarial densities (MFD). Therefore, ivermectin MDA is not recommended in areas where onchocerciasis is hypo-endemic and L. loa is co-endemic. To eliminate onchocerciasis in those areas, a test-and-not-treat (TaNT) strategy has been proposed. We investigated whether onchocerciasis elimination can be achieved using TaNT and the required duration. Methods We used the individual-based model ONCHOSIM to predict the impact of TaNT on onchocerciasis microfilarial (mf) prevalence. We simulated pre-control mf prevalence levels from 2-40%. The impact of TaNT was simulated under varying levels of participation, systematic non-participation and exclusion from ivermectin due to high L. loa MFD. For each scenario, we assessed the time to elimination, defined as bringing onchocerciasis mf prevalence below 1.4%. Results In areas with 30-40% pre-control mf prevalence, the model predicted that it would take between 14 and 16 years to bring the mf prevalence below 1.4% using conventional MDA, assuming 65% participation. TaNT would increase the time to elimination by up to 1.5 years, depending on the level of systematic non-participation and the exclusion rate. At lower exclusion rates (≤2.5%), the delay would be less than six months. Conclusions Our model predicts that onchocerciasis can be eliminated using TaNT in L. loa co-endemic areas. The required treatment duration using TaNT would be only slightly longer than in areas with conventional MDA, provided that participation is good.

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