Concurrent parasitic infections among patients with onchocerciasis and controls in Sierra Leone, West Africa

Molecular identification of Physaloptera sp. from wild northern bobwhite (Colinus virginianus) in the Rolling Plains ecoregion of Texas

Physaloptera spp. are common nematodes found in the stomach and muscles of mammals, reptiles, amphibians, and birds. Physaloptera spp. have a complicated life cycle with multiple definitive hosts, arthropod intermediate hosts, aberrant infections, and possible second intermediate hosts or paratenic hosts. For example, Physaloptera sp. larvae have been found within the tissues of wild northern bobwhite quail (Colinus virginianus), and it is suspected that quail may serve as paratenic or secondary hosts of these parasites. However, because it is not known what role quail play in the life cycle of Physaloptera spp. and descriptions of Physaloptera spp. larvae are limited, molecular tools may be beneficial when identifying these helminths. In this study, we generated primers using universal nematode primers and obtained a partial mitochondrial cytochrome oxidase 1 (COX 1) sequence. Morphological identification of Physaloptera sp. in bobwhite was confirmed via polymerase chain reaction (PCR), and a phylogenetic tree was constructed using the maximum likelihood method. BLAST analysis revealed a strong identity to other Physaloptera spp. and the phylogenetic tree placed all Physaloptera spp. in the same cluster. We also documented a marked increase in Physaloptera infections in bobwhite from 2017 to 2018, and the similarity of these parasites to Onchocerca volvulus and Wuchereria bancrofti may give insight into the increased prevalence we observed. This study demonstrates the usefulness of molecular techniques to confirm the identity of species that may lack adequate descriptions and provides new insight for the diagnosis and potentially overlooked significance of Physaloptera sp. infections of bobwhite in the Rolling Plains ecoregion of Texas.

Polyparasite helminth infections and their association to anaemia and undernutrition in Northern Rwanda

BACKGROUND

Intestinal schistosomiasis and soil-transmitted helminth (STH) infections constitute major public health problems in many parts of sub-Saharan Africa. In this study we examined the functional significance of such polyparasite infections in anemia and undernutrition in Rwandan individuals.

METHODS

Three polyparasite infection profiles were defined, in addition to a reference profile that consisted of either no infections or low-intensity infection with only one of the focal parasite species. Logistic regression models were applied to data of 1,605 individuals from 6 schools in 2 districts of the Northern Province before chemotherapeutic treatment in order to correctly identify individuals who were at higher odds of being anaemic and/or undernourished.

FINDINGS

Stunted relative to nonstunted, and males compared to females, were found to be at higher odds of being anaemic independently of polyparasite infection profile. The odds of being wasted were 2-fold greater for children with concurrent infection of at least 2 parasites at M+ intensity compared to those children with the reference profile. Males compared to females and anaemic compared to nonanaemic children were significantly more likely to be stunted. None of the three polyparasite infection profiles were found to have significant effects on stunting.

CONCLUSION

The present data suggest that the levels of polyparasitism, and infection intensities in the Rwandan individuals examined here may be lower as compared to other recent similar epidemiological studies in different regions across sub-Saharan Africa. Neither the odds of anaemia nor the odds of stunting were found to be significantly different in the three-polyparasite infection profiles. However, the odds of wasting were higher in those children with at least two parasites at M+ intensity compared to those children with the reference profile. Nevertheless, despite the low morbidity levels indicated in the population under study here, we recommend sustainable efforts for the deworming of affected populations to be continued in order to support the economic development of the country.

The synergistic effect of concomitant schistosomiasis, hookworm, and trichuris infections on children's anemia burden

OBJECTIVE

To estimate the degree of synergism between helminth species in their combined effects on anemia.

METHODS

Quantitative egg counts using the Kato-Katz method were determined for Ascaris lumbricoides, hookworm, Trichuris trichiura, and Schistosoma japonicum in 507 school-age children from helminth-endemic villages in The Philippines. Infection intensity was defined in three categories: uninfected, low, or moderate/high (M+). Anemia was defined as hemoglobin <11 g/dL. Logistic regression models were used to estimate odds ratios (OR), 95% confidence intervals (CI), and synergy index for pairs of concurrent infections.

RESULTS

M+ co-infection of hookworm and S. japonicum (OR = 13.2, 95% CI: 3.82-45.5) and of hookworm and T. trichiura (OR = 5.34, 95% CI: 1.76-16.2) were associated with higher odds of anemia relative to children without respective M+ co-infections. For co-infections of hookworm and S. japonicum and of T. trichiura and hookworm, the estimated indices of synergy were 2.9 (95% CI: 1.1-4.6) and 1.4 (95% CI: 0.9-2.0), respectively.

CONCLUSION

Co-infections of hookworm and either S. japonicum or T. trichiura were associated with higher levels of anemia than would be expected if the effects of these species had only independent effects on anemia. This suggests that integrated anti-helminthic treatment programs with simultaneous deworming for S. japonicum and some geohelminths could yield a greater than additive benefit for reducing anemia in helminth-endemic regions.

Analysis of Wuchereria bancrofti infections in a village community in northern Nigeria: increased prevalence in individuals infected with Onchocerca volvulus

Infections with Wuchereria bancrofti causing lymphatic filariasis still represent one of the major health problems in the tropics, with 120 million people infected and over 750 million exposed to this filarial parasite. We have studied lymphatic filariasis infections as part of a multi-parasite survey in a village community in the savannah of northern Nigeria. We analysed serum samples from 341 individuals aged 5-70 years, detecting a W. bancrofti circulating antigen using the commercially available ICT Filariasis card test. The prevalence of infections was 10% and clearly age-dependent, increasing from below 2% in children to over 20% in subjects older than 40 years. Measuring IgG4 antibodies against the recombinant W. bancrofti antigen SXP1 showed that 36% of all tested individuals had been at least exposed to the parasite. Antibody levels also increased very significantly with age. A further analysis measuring Onchocerca volvulus-specific IgG4 antibodies showed a very significant association between infections with O. volvulus and those with W. bancrofti. Our data show that infections with W. bancrofti in Nigeria are still a frequently occurring health problem, since they are more prevalent than previously reported, and that individuals with an O. volvulus infection are more often infected with W. bancrofti than expected statistically.

Serodiagnosis of imported schistosomiasis by a combination of a commercial indirect hemagglutination test with Schistosoma mansoni adult worm antigens and an enzyme-linked immunosorbent assay with S. mansoni egg antigens

A commercial indirect hemagglutination (IHA) test using erythrocytes coated with Schistosoma mansoni adult worm antigens (WA) and an enzyme-linked immunosorbent assay (ELISA) with S. mansoni egg antigens (SEA) were assessed for their use in serodiagnosis of imported schistosomiasis (hereafter these tests are designated WA/IHA and SEA/ELISA, respectively). The sensitivity of the tests was evaluated with sera from 75 patients with proven S. mansoni infection, 25 with proven S. haematobium infection, and 10 with clinical Katayama fever. The specificity was assessed with sera from 283 patients with various parasitic, bacterial, viral, and fungal infections and sera containing autoimmune antibodies. Sensitivities of the WA/IHA with a cutoff titer of 1:160 (WA/IHA(160)) in detecting S. mansoni, S. haematobium, S. mansoni and S. haematobium combined, and clinical Katayama fever were 88.0, 80.0, 86.0, and 70.0%, respectively, with a specificity of 98.9%. The WA/IHA with a cutoff of 1:80 (WA/IHA(80)) showed sensitivities of 94.7, 92.0, 94.0, and 90.0%, respectively, with a specificity of 94.7%. The comparable values of SEA/ELISA were 93.3, 92.0, 93.0, and 50.0%, respectively, with a specificity of 98.2%. Combined use of ELISA and WA/IHA(80) gave sensitivities of 100% for S. mansoni, S. haematobium, and S. mansoni and S. haematobium combined and 90% for Katayama fever. The specificity of this combination in detecting schistosomiasis was 92.9%. Combination of SEA/ELISA with WA/IHA(160) gave sensitivities of 98.7, 96.0, 98.0, and 80% with a specificity of 97.2%. Our findings suggest that WA/IHA and SEA/ELISA are each sensitive and specific serological tests that are easy to use for the diagnosis of imported schistosomiasis. The combined use of these two tests enabled the serological diagnosis of schistosomiasis to be achieved with very high degrees of both sensitivity and specificity.