South Asian Journal of Parasitology

Leucocytozoonosis in Desi Birds and a Review on the Etiology of Anemia in Desi Birds

2026-09-16T06:43:54+00:00

Leucocytozoonosis is a haemoprotozoan disease of domestic and wild birds caused by species of the genus Leucocytozoon and transmitted by blood-sucking vectors. Indigenous desi chickens reared under extensive or semi-intensive backyard systems may experience substantial vector exposure and can present with non-specific signs of disease. This article describes a clinical case in a two-year-old male Aseel chicken presented with a pale comb, depression, anorexia, ruffled feathers, and open-mouth breathing. Examination of a Giemsa-stained peripheral blood smear demonstrated Leucocytozoon spp. gametocytes, while haematological findings showed reduced haemoglobin (8 g/dL) and packed cell volume (25%). The bird showed clinical improvement following treatment with primaquine in combination with sulfamethoxazole and trimethoprim, together with supportive therapy. The review component outlines the pathogenesis, diagnosis, treatment, and prevention of leucocytozoonosis and considers the broader differential aetiology of anaemia in desi birds. Major mechanisms discussed include haemorrhagic and haemolytic anaemia associated with trauma, gastrointestinal parasites, ectoparasites, and haemoparasites, as well as non-regenerative anaemia related to nutritional deficiency, chronic disease, toxins, and disorders affecting haematopoiesis. The case and review together emphasise differentiation between regenerative and non-regenerative mechanisms when evaluating anaemia in backyard poultry. An integrated diagnostic approach combining history, clinical examination, haematology, blood-smear assessment, parasitological investigation, and targeted infectious-disease testing is emphasised for case interpretation and flock-level management.

Evidence of Ivermectin Resistance in Sarcoptes scabiei var. canis Infesting Dogs: A Clinical and in vitro Study

2026-09-02T13:07:03+00:00

Sarcoptic mange caused by Sarcoptes scabiei var. canis is a contagious canine dermatosis, and apparent ivermectin treatment failure raises concern about reduced acaricide susceptibility. This study evaluated the clinical response to a three-dose ivermectin protocol and compared in vitro ivermectin susceptibility between mites recovered from clinically refractory dogs and a reference susceptible isolate. Thirty naturally infested dogs received subcutaneous ivermectin at 300 µg/kg on days 0, 14, and 28, with serial skin scrapings and pruritus assessment through day 42. Mites from refractory dogs were pooled as a field-resistant isolate and tested against a susceptible isolate using ivermectin contact bioassays. Twenty-four dogs (80%) became mite-negative with more than 75% pruritus resolution, whereas six dogs (20%) remained mite-positive with less than 25% pruritus reduction and were classified as clinically refractory. At 1% ivermectin, 24-hour mortality was 34% in the field-resistant isolate compared with 91% in the susceptible isolate. The 24-hour LC₅₀ was 0.71% for the field-resistant isolate and 0.09% for the susceptible isolate, corresponding to a resistance ratio of approximately 7.9. LT₅₀ at 1% increased from 2.1 to 9.4 hours. These findings are consistent with a marked phenotypic reduction in ivermectin susceptibility associated with clinical treatment failure and support confirmatory follow-up testing, careful acaricide selection, and continued surveillance.

Investigating the Potential Role of Invasive Golden Apple Snail Pomacea canaliculata in the Transmission of Schistosomiasis in Mwea, Kirinyaga County, Kenya

2026-09-07T09:19:32+00:00

Schistosomiasis is a major public health challenge in irrigation-based communities. The recent establishment of the invasive snail, Pomacea canaliculata, within the Mwea Irrigation Scheme has raised concerns regarding its interaction with native vector snails and its potential influence on schistosomiasis transmission. However, its ecological relationship with native vector snails and the temporal patterns of reported human schistosomiasis following its establishment remain unclear. This study aimed to evaluate ecological and epidemiological evidence for the potential indirect role of P. canaliculata in schistosomiasis transmission by assessing its spatiotemporal distribution and abundance relative to native vector snails and examining temporal trends in reported human schistosomiasis following its establishment. A cross-sectional survey was conducted at 32 sites in irrigation canals and rice paddies during the rainy and dry seasons to assess snail distribution and abundance, while hospital surveillance records for 2019–2025 were analysed for temporal trends. Seasonal and habitat-related differences in snail abundance were assessed using non-parametric tests, while temporal trends in reported human schistosomiasis were evaluated using linear regression and Kendall’s tau correlation. P. canaliculata occurred at all 32 sites, with significantly higher abundance during the rainy season and in irrigation canals (p ≤ 0.05). Native vector snails were absent from 18 (56.2%) sites occupied by P. canaliculata and co-occurred at 14 (43.8%) sites. Reported human schistosomiasis cases declined by 86.7% between 2019 and 2025, with a significant overall temporal decline. The widespread establishment of P. canaliculata, its occurrence where native vector snails were absent, and the concurrent decline in reported human schistosomiasis following its establishment suggest a potential indirect role in transmission through ecological effects on native vector snail populations. However, temporal ecological changes cannot be established from a cross-sectional study. Longitudinal studies are therefore required to determine whether the continued establishment of P. canaliculata results in measurable changes in native vector snail populations and schistosomiasis transmission over time.

Malaria Parasitaemia among Pregnant Women Attending Antenatal Care in Minna, Nigeria: A Historical Cross-Sectional Study from 2008

2026-09-17T12:32:58+00:00

Background: Malaria remains an important health concern among pregnant women in sub-Saharan Africa, with substantial variation in infection prevalence across populations, locations and diagnostic approaches. Historical data can provide useful epidemiological context for understanding past malaria burden and patterns. However, documented evidence from pregnant women attending antenatal care in Minna, Nigeria, during the earlier period remains limited, warranting analysis of the available 2008 dataset.

Aims: To describe the prevalence and distribution of microscopy-detected Plasmodium infection among pregnant women attending antenatal care at Minna General Hospital, Niger State, Nigeria, between May and July 2008, using the surviving historical aggregate data.

Study design: Historical cross-sectional design.

Place and Duration of Study: Department of Medical Laboratory Science and Antenatal Clinic, Minna General Hospital, Minna, Niger State, Nigeria, between May and July 2008.

Methodology: A total of 230 pregnant women were included. Information on malaria positivity, maternal age, gestational trimester, parity and Plasmodium species was retrieved from the subjects. Thick and thin blood films were prepared and stained with Giemsa and examined microscopically. Prevalence estimates were recalculated with 95% Wilson confidence intervals. Pearson chi-square tests were used for unadjusted associations with age group, trimester and parity.

Results: Plasmodium parasites were detected in 109/230 women (47.4%, 95% CI 41.0–53.8). Among positive samples, 106 (97.2%) were reported as Plasmodium falciparum and 3 (2.8%) as P. malariae. Positivity did not differ significantly by age group (χ²=6.65, df=4, p=0.155) or parity (χ²=0.21, df=1, p=0.645). Positivity varied across trimester categories (χ²=11.76, df=2, p=0.0028), with prevalence of 54.8% in the first trimester, 56.9% in the second and 33.3% in the third.

Conclusion: Microscopy-detected Plasmodium infection was common among the pregnant women represented in this historical Minna dataset in 2008. P. falciparum predominated. The trimester pattern should be interpreted as an unadjusted cross-sectional association rather than evidence of a causal effect of gestational age. These findings are best regarded as a historical reference point rather than a contemporary prevalence estimate.

Parasitological Profiles of Fish from Petroleum-Impacted Freshwater Ecosystems in Delta State, Nigeria

2026-09-18T06:20:39+00:00

This study assessed the parasitological profiles of fish from petroleum-impacted freshwater ecosystems in Delta State, Nigeria, and examined spatial associations between petroleum contamination and parasite burden. A total of 300 fish representing six freshwater species were collected from five sampling stations and examined for ectoparasites and endoparasites using standard parasitological procedures. Water samples were analysed for total petroleum hydrocarbons (TPH) and total polycyclic aromatic hydrocarbons (PAHs), while parasite prevalence, mean intensity and mean abundance were determined. Overall, 126 fish were infected, giving a prevalence of 42.0%. Clarias gariepinus had the highest prevalence (53.3%), whereas Chrysichthys nigrodigitatus had the lowest (30.0%). A total of 218 parasites were recovered; nematodes were most abundant (31.2%), followed by trematodes, cestodes, acanthocephalans and protozoans. The gastrointestinal tract accounted for 48.2% of recovered parasites. Parasite prevalence varied spatially from 26.7% at S1 to 58.3% at S4, and mean intensity ranged from 1.38 to 2.09. TPH concentrations ranged from 2.84 ± 0.31 to 14.72 ± 1.06 mg/L, with S4 recording the highest petroleum burden and parasitological indices. Petroleum contamination showed positive associations with parasite prevalence and mean intensity. These findings indicate substantial spatial variation in fish parasitism and support integrating parasitological indicators with petroleum monitoring in freshwater ecosystem assessment.